Versickerung und Retention/en: Unterschied zwischen den Versionen

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Advantages of rainwater infiltration
 
Advantages of rainwater infiltration
  
'''For final consumers:'''
+
'''For end users:'''
*sealing costs are saved
+
*stormwater fees are saved
*the microclimate on site is improved
+
*the local microclimate is improved
 
'''For municipalities:'''
 
'''For municipalities:'''
*lower flood protection / flood prevention costs
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*lower costs for flood protection / flood prevention
*lower costs in sewer construction, sewer rehabilitation and sewage plant operation
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*lower costs for sewer construction, sewer rehabilitation and sewage plant operation
*lower development costs for new estates
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*lower connection costs for new developments
*securing of the groundwater supply
+
*protection of the groundwater supply
  
 
'''Advantages of rainwater retention:'''
 
'''Advantages of rainwater retention:'''
*limiting regional flowing off, reducing flood risk
+
*limiting area discharge, reducing flood risk
 
*lower costs in sewer construction, sewer rehabilitation and sewage plant operation
 
*lower costs in sewer construction, sewer rehabilitation and sewage plant operation
*connection of new estates to existing, working at full capacity drainage systems
+
*connection of new developments to existing, full-capacity drainage systems
*relief of overloaded sewer systems
+
*relief of overloaded sewer networks
  
 
=Basic principles=
 
=Basic principles=
Zeile 32: Zeile 32:
 
Tolerable rainwater runoff can be infiltrated through the unsaturated zone after suitable pretreatment or using cleaning processes (sedimentation system, rainwater cisterns, overgrown soil, etc.).
 
Tolerable rainwater runoff can be infiltrated through the unsaturated zone after suitable pretreatment or using cleaning processes (sedimentation system, rainwater cisterns, overgrown soil, etc.).
  
 +
===Intolerable rainwater runoff===
 
Intolerable rainwater runoff can only be infiltrated after pretreatment.
 
Intolerable rainwater runoff can only be infiltrated after pretreatment.
  
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</table>
 
</table>
  
 
+
'''Trough-trench infiltration with DRAINMAX Tunnel'''
'''Mulden-Rigolenversickerung mit DRAINMAX Tunnel'''
 
  
 
[[Datei:RWV_Mulden_Rigolenversickerung_DM.png |600px | Trough-trench infiltration with DRAINMAX Tunnel]]
 
[[Datei:RWV_Mulden_Rigolenversickerung_DM.png |600px | Trough-trench infiltration with DRAINMAX Tunnel]]
Zeile 130: Zeile 130:
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">2. seitliche und obere Tunnelverfüllung</td>
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<td style="width:50%; text-align: left; vertical-align: top">2. Tunnel side and top backfil</td>
<td style="width:50%; text-align: left; vertical-align: top">7. Regenwasserzulauf</td>
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<td style="width:50%; text-align: left; vertical-align: top">7. Rainwater inlet</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">3. Geotextil</td>
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<td style="width:50%; text-align: left; vertical-align: top">3. Geotextile</td>
<td style="width:50%; text-align: left; vertical-align: top">8. Grundwasserabstand</td>
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<td style="width:50%; text-align: left; vertical-align: top">8. Distance to groundwater</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">4. Tunnelüberdeckung</td>
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<td style="width:50%; text-align: left; vertical-align: top">4. Tunnel overburden</td>
<td style="width:50%; text-align: left; vertical-align: top">9. belebte Bodenzone</td>
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<td style="width:50%; text-align: left; vertical-align: top">9. Active soil zone</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">5. Oberboden</td>
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<td style="width:50%; text-align: left; vertical-align: top">5. Topsoil</td>
<td style="width:50%; text-align: left; vertical-align: top">10. maximaler Wasserstand</td>
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<td style="width:50%; text-align: left; vertical-align: top">10. Maximum water level</td>
 
</tr>
 
</tr>
 
</table>
 
</table>
Zeile 149: Zeile 149:
  
  
'''Trough-trench infiltration with DRAINMAX Tunnel'''
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'''DRAINMAX Tunnel System for commercial properties'''
  
[[Datei:RWV_System_Gewerbeobjekte_DM.png |600px | DRAINMAX Tunnel System für Gewerbeobjekt]]
+
[[Datei:RWV_System_Gewerbeobjekte_DM.png |600px| DRAINMAX Tunnel System for commercial properties]]
 
<table style="width:600px">
 
<table style="width:600px">
 
<tr>  
 
<tr>  
 
<td style="width:50%; text-align: left; vertical-align: top"> 1. DRAINMAX Tunnel</td>  
 
<td style="width:50%; text-align: left; vertical-align: top"> 1. DRAINMAX Tunnel</td>  
<td style="width:50%; text-align: left; vertical-align: top"> 7. Sedimentations-/Filterschacht</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 7. Sedimentation/filter chamber</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">2. seitliche und obere Tunnelverfüllung</td>
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<td style="width:50%; text-align: left; vertical-align: top">2. Tunnel side and top backfill</td>
<td style="width:50%; text-align: left; vertical-align: top">8. Spülschacht</td>
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<td style="width:50%; text-align: left; vertical-align: top">8. Flushing chamber</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">3. Geotextil</td>
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<td style="width:50%; text-align: left; vertical-align: top">3. Geotextile</td>
<td style="width:50%; text-align: left; vertical-align: top">9. Regenwasserzulauf</td>
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<td style="width:50%; text-align: left; vertical-align: top">9. Rainwater inlet</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">4. Tunnelüberdeckung</td>
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<td style="width:50%; text-align: left; vertical-align: top">4. Tunnel overburden</td>
<td style="width:50%; text-align: left; vertical-align: top">10. Grundwasserabstand</td>
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<td style="width:50%; text-align: left; vertical-align: top">10. Maximum water level</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">5. Oberboden</td>
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<td style="width:50%; text-align: left; vertical-align: top">5. Topsoil</td>
<td style="width:50%; text-align: left; vertical-align: top">11. Geoverbundstoffunterlage</td>
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<td style="width:50%; text-align: left; vertical-align: top">11. Geotextile composite bottom layer</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top">6. Regenwasserverteilung</td>
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<td style="width:50%; text-align: left; vertical-align: top">6. Rainwater distribution</td>
 
<td style="width:50%; text-align: left; vertical-align: top"> </td>
 
<td style="width:50%; text-align: left; vertical-align: top"> </td>
 
</tr>
 
</tr>
 
</table>
 
</table>
  
=Aufbau einer Retentionsanlage=
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=Construction of a retention system=
==Rückhaltevolumen==
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==Retention volume==
[[Datei:RWV Drosselablauf.jpg |miniatur|200px|Rückhaltezisterne mit Drosselablauf]]
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[[Datei:RWV Drosselablauf.jpg |miniatur|200px|Retention cistern with throttle discharge]]
[[Datei:RWN DrosselablaufNutzvolumen.png.jpg|miniatur|200px|Rückhaltezisterne mit Drosselablauf und Nutzvolumen]]
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[[Datei:RWN DrosselablaufNutzvolumen.png.jpg|miniatur|200px|Retention cistern with throttle discharge and usable volume]]
  
Für die Rückhaltung des Regenwassers gibt es verschiedene Möglichkeiten:
+
There are several options for the retention of rainwater:
  
* Speicher mit reiner Rückhaltung und Drosselablauf
+
*Storage with pure retention and throttle discharge
* Speicher mit kombinierter Rückhaltung und Nutzung und Drosselablauf
+
*Storage with combined retention and use and throttle discharge
  
  
Die Kombination von Regenwassernutzung und Regenwasserretention in einer Zisterne ist bei kleineren Systemen im Einfamilienhausbereich besonders interessant, da die Kosten für Erdaushub und Lieferung nur einmal anfallen und auch die Zisterne nicht wesentlich teurer ist.
+
The combination of rainwater harvesting and rainwater retention in a cistern is particularly interesting for smaller systems for single-family homes since the costs for excavation and delivery are incurred only once and the cistern is not significantly more expensive.
  
* Retention mit zulässiger Teilversickerung und Drosselablauf
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* Retention with approved partial infiltration and throttle discharge
  
  
Bei zulässiger Teilversickerung ist das [https://www.intewa.de/anwendungen/regenwassermanagement/rw-rueckhaltung/ DRAINMAX] System mit Tunnelelementen eine äußerst interessante Alternative. Der geringe Höhenversatz zwischen Zu- und Ablauf in Kombination mit großer räumlicher Flexibilität und einem sehr hohen Speichervolumen sind die Vorzüge dieser Variante. Wenn kein Wasser aus dem System in das umgebende Erdreich gelangen darf, kann es mit einer EPDM Folie bauseits abgedichtet werden
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With permitted partial infiltration, the [https://www.intewa.de/en/products/drainmax/ DRAINMAX] system with tunnel elements is an extremely interesting alternative. The low height offset between inlet and outlet in combination with large space flexibility and a very high storage volume are the advantages of this variant. If no water is allowed to enter the surrounding soil from the system, it can be sealed with an EPDM foil on site.
  
[[Datei:RWV_DM_System.png|600px|DRAINMAX Tunnel System]]
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[[Datei:RWV_DM_System.png|600px|DRAINMAX Tunnel system]]
 
<table style="width:600px">
 
<table style="width:600px">
 
<tr>  
 
<tr>  
 
<td style="width:50%; text-align: left; vertical-align: top"> 1. DRAINMAX Tunnel</td>  
 
<td style="width:50%; text-align: left; vertical-align: top"> 1. DRAINMAX Tunnel</td>  
<td style="width:50%; text-align: left; vertical-align: top"> 6. Oberboden</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 6. Topsoil</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top"> 2. seitliche und obere Tunnelverfüllung</td>
+
<td style="width:50%; text-align: left; vertical-align: top"> 2. Tunnel side and top backfill</td>
<td style="width:50%; text-align: left; vertical-align: top"> 7. Sedimentations-/Filterschacht</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 7. Sedimentation/filter  chamber</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top"> 3. Geotextil</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 3. Geotextile</td>
<td style="width:50%; text-align: left; vertical-align: top"> 8. Drosselschacht</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 8. Throttle chamber</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top"> 4. Folienwanne aus EPDM und Geotextil</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 4. Enclosed sheet basin made from EPDM and geotextile</td>
<td style="width:50%; text-align: left; vertical-align: top"> 9. Ablaufdrossel</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 9. Discharge throttle</td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td style="width:50%; text-align: left; vertical-align: top"> 5. Tunnelüberdeckung</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 5. Tunnel overburden</td>
<td style="width:50%; text-align: left; vertical-align: top"> 10. Regenwasserzulauf</td>
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<td style="width:50%; text-align: left; vertical-align: top"> 10. Rainwater inlet</td>
 
</tr>
 
</tr>
 
</table>
 
</table>
  
==Drosselabfluss==
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==Throttle discharge==
  
Bei einer Retentionsanlage wird das Wasser über einen gedrosselten Volumenstrom der Entwässerungseinrichtung zugeführt. Der Drosselabfluss entspricht dem zulässigen Abfluss des versiegelten Gebietes in die Entwässerungseinrichtung. Meist entspricht dieser Abfluss dem natürlichen Abfluss vor der Versiegelung.
+
In a retention system the water is supplied into the drainage system with a throttled flow rate. The throttle discharge corresponds to the permitted outflow of the sealed area connected to the drainage system. Most of the time this discharge corresponds to the natural flow before sealing the area.
  
Der zulässige Drosselabfluss wird bei einem Retentionssystem entweder mit einer Hebepumpe in das nachgeschaltete Entwässerungssystem geleitet oder über eine Ablaufdrossel abgeführt, falls dies die Höhenverhältnisse zulassen.  
+
In the retention system the permissible throttle discharge is either supplied to a downstream drainage system by means of a lift pump or through a discharge throttle provided the height conditions allow. According to DWA-A 117, the arithmetic average of the values of the throttle curve is to be set for uncontrolled throttling (fixed throttle/vortex throttle).
Laut DWA-A 117 soll bei ungeregelten Drosseln (starre Drossel/Wirbeldrossel) das arithmetische Mittel der Werte der Drosselkennlinie angesetzt werden.
 
  
Kontinuierliche Drosseln sorgen im Vergleich zu Wirbeldrosseln oder starren Drosseln dafür, dass unabhängig von der Einstauhöhe H ständig die maximal zulässige Wassermenge Q  abfließt. Hierdurch können die Retentionsspeicher mit kontinuierlichen Drosseln um 10 % bis 30 % kleiner dimensioniert werden als bei starren Ablaufdrosseln oder Wirbeldrosseln.
+
Compared to the vortex or fixed throttle, continuous throttles make sure that the maximum permitted water quantity Q drains constantly, irrespective of the impounding depth H. As a result, the retention tank with continuous throttle can be dimensioned by 10% to 30% smaller than with fixed throttle discharge or vortex throttles.
  
[[Datei:starreDrossel.png|miniatur|200px|starre Drossel]]
+
[[Datei:starreDrossel.png|miniatur|200px|Fixed throttle]]
[[Datei:Wirbeldrossel.png|miniatur|200px|Wirbeldrossel]]
+
[[Datei:Wirbeldrossel.png|miniatur|200px|Vortex throttle]]
[[Datei:KontinuierlicheDrossel.png|miniatur|200px|kontinuierliche Drossel]]
+
[[Datei:KontinuierlicheDrossel.png|miniatur|200px|Continuous throttle]]
  
Bsp. Drosselkennlinien für eine maximal zulässige Wassermenge von 31 l/s
+
Exp. throttle curve for maximum admissible water quantity of 31 L/s
  
[[Datei:Drosseldiagramm.png |300px| Drosseldiagramm]]
+
[[Datei:Drosseldiagramm.png|300px|Throttle diagram]]
  
1. Starre Drossel (arithmetisches Mittel hier = 21 l/s)
+
1. Fixed throttle (arithmetic mean = 21 L/s)
  
2. Wirbeldrossel (arithmetisches Mittel hier = 21 l/s)
+
2. Vortex throttle (arithmetic mean = 21 L/s)
  
3. Kontinuierliche Ablaufdrossel (31 l/s)
+
3. Continuous discharge throttle (31 L/s)
  
  
  
===Starre Drossel===
+
===Fixed throttle===
Die einfachste Form einer starren oder statischen Drossel ist eine einfache Drosselblende. Der Abflusswert Q der starren Drossel ist abhängig vom hydrostatischen Druck, der sich aus der Einstauhöhe H ergibt.
+
The simplest form of a fixed or static throttle is a simple flow restrictor. The discharge value Q of the fixed throttle depends on the hydrostatic pressure resulting from the impounding depth H.
  
===Wirbeldrossel===
+
===Vortex throttle===
Bei einer Wirbeldrossel entsteht durch die tangentiale Beschickung in Abhängigkeit vom Wasserstand eine unterschiedlich starke Spiralströmung mit einem zentrischen Luftwirbelkern. Dies führt jedoch nicht zu einem kontinuierlichen Drosselabfluss. Zu den Vorteilen der Wirbeldrossel gehören der geringe Platzbedarf und die geringe Gefahr von Verstopfungen durch den größeren  verbleibenden Querschnitt im Vergleich zu den anderen Drosseltypen. Diese Vorteile sind bei der dezentralen Regenwasserrückhaltung aber selten relevant.
+
A spiral stream of variable strength with a central rotating air core is formed by the tangential feed in the vortex throttle depending on the water level. However this does not lead to a continuous throttle outflow. The vortex throttle has the advantage of requiring less space and lower risk of blockages due to the larger remaining cross-section compared to the other throttle types. These advantages are rarely relevant with decentralized rainwater retention.
  
===Kontinuierliche Drossel===
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===Continuous throttle===
Bei der kontinuierlichen Ablaufdrossel ist der Abflusswert unabhängig von der Einstauhöhe H konstant. Der Schwimmer passt dazu über den Hebelarm die Blendenöffnung an die Einstauhöhe an. Eine grobe Vorreinigung des Regenwassers ist für den störungsfreien Betrieb der Drossel erforderlich.
+
The outlet flow is constant with the continuous discharge throttle irrespective of the impounding depth H. The float adjusts the restrictor opening at the impounding depth by means of a lever arm. Coarse pre-cleaning of rainwater is necessary for the trouble-free operation of the throttle.
  
  
===Berechnungsbeispiel erforderliches Speichervolumen===
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===Calculation example of required storage volume===
Die maßgebliche Regenspende r<sub>D(n)</sub> der Dauerstufe D und Häufigkeit n [l/sha] muss im Vorfeld iterativ bestimmt werden (siehe Bemessung von Versickerungs- oder Retentionsanlagen).
+
The crucial rain yield  r<sub>D(n)</sub>, the duration D and frequency n [L/s-ha] must be determined iteratively (see Dimensioning of infiltration or retention systems).
  
 
{| class="wikitable"
 
{| class="wikitable"
 
|colspan="2" style="text-align:center"  | '''V<sub>erf</sub> = ((A<sub>red</sub> x r<sub>D(n)</sub> x 10<sup>-4</sup>) – Q<sub>dr</sub> ) x D x 60 x 10<sup>-3</sup>'''
 
|colspan="2" style="text-align:center"  | '''V<sub>erf</sub> = ((A<sub>red</sub> x r<sub>D(n)</sub> x 10<sup>-4</sup>) – Q<sub>dr</sub> ) x D x 60 x 10<sup>-3</sup>'''
 
|-
 
|-
| V<sub>erf</sub> || = erforderliches Speichervolumen in m³
+
| V<sub>erf</sub> || = required storage volume in m³
 
|-
 
|-
| A<sub>red</sub> || = angeschlossene befestigte Fläche in m² (im Beispiel 5.000 m²)
+
| A<sub>red</sub> || = connected paved surfaces in m² (5,000 m² in example)
 
|-
 
|-
| r<sub>D(n)</sub> || = maßgebende Regenspende in l/sha (Bsp. KOSTRA-Daten Aachen, s. Bemessung von Versickerungs- oder Retentionsanlagen)
+
| r<sub>D(n)</sub> || = crucial rainfall in L/sha (e.g. KOSTRA-Data Aachen, see Dimensioning of infiltration or retention systems)
 
|-
 
|-
| Q<sub>dr</sub>  || = Abflussdrosselwert in l/s (bei nicht kontinuierlichen Drosseln das arithmetische Mittel der Drosselkennlinie, s. Diagramm Drosselkennlinien, im Beispiel 21 l/s)
+
| Q<sub>dr</sub>  || = discharge throttle value in L/s (the arithmetic mean of the throttle curve with non-continuous throttles, see diagram of throttle curves, 21 L/s in the example)
 
|-
 
|-
| D || = Dauerstufe in min (im Beispiel 30 min bei der starren Drossel und Wirbeldrossel, 20 min bei der kontinuierlichen Drossel)
+
| D || = Duration in min (in example, 30 min with the fixed throttle and vortex throttle, 20 min with the continuous throttle)
 
|-
 
|-
|colspan="2" style="text-align:left" | '''starre Drossel = Wirbeldrossel:''' V<sub>erf</sub> = ((5.000 x 104,8 x 10<sup>-4</sup>) – 21) x 30 x 60 x 10<sup>-3</sup> = 56,6 m³
+
|colspan="2" style="text-align:left" | '''fixed throttle = vortex throttle:''' V<sub>erf</sub> = ((5,000 x 104.8 x 10<sup>-4</sup>) – 21) x 30 x 60 x 10<sup>-3</sup> = 56.6 m³
 
|-
 
|-
|colspan="2" style="text-align:left" | '''kontinuierliche Drossel:''' V<sub>erf</sub> = ((5.000 x 131,7 x 10<sup>-4</sup>) – 31) x 20 x 60 x 10-3 = 41,8 m³ (- 26 %)
+
|colspan="2" style="text-align:left" | '''continuous throttle:''' V<sub>erf</sub> = ((5,000 x 131.7 x 10<sup>-4</sup>) – 31) x 20 x 60 x 10-3 = 41.8 m³ (- 26 %)
 
|}
 
|}
  
Je größer der erlaubte Drosselabfluss im Verhältnis zu angeschlossenen Fläche ist, desto größer ist der Unterschied. Dieser Unterschied führt zu entsprechend geringeren Gesamtkosten für das Rückhaltesystem.
+
The larger the permitted throttle outflow in relation to the connected areas, the greater the difference. This difference leads to correspondingly lower total costs for the retention system.
  
=Bemessung von Versickerungs- und Retentionsanlagen=
+
=Dimensioning of infiltration or retention systems=
siehe auch [https://www.intewa.de/online-planer/ Online Planer]
+
Also see [https://www.intewa.de/en/online-planner/ Online Planner]
  
==Regenwasserabfluss==
+
==Rainwater runoff==
Die Berechnung des Regenabflusses geht von der Erkenntnis aus, dass starke Regenfälle von kurzer Dauer sind, schwache Regen dagegen länger anhalten. Die Regenspende nimmt bei gleicher statistischer Häufigkeit mit zunehmender Regendauer also ab. Der Zusammenhang zwischen Regenspende, Regendauer und Häufigkeit wird durch die statistische Auswertung von Niederschlagsregistrierungen ermittelt.
+
The calculation of rainwater runoff is based on the knowledge that heavy rains last short durations and low rains persist for longer. The rainfall yield declines at the same statistical frequency with increasing rainfall duration. The relationship between rainfall yield, duration and frequency is determined by the statistical analysis of precipitation registrations. Simple calculation methods in Germany are used in accord with DWA-A 117. For this a statistical rainfall with selected duration '''D''' and frequency '''n''' should be used as load case for calculation. For the determination of rain yield refer to the "amount of heavy peak rainfall in Germany - KOSTRA" (see table for a sample location).
Im Allgemeinen wird in Deutschland das einfache  Bemessungsverfahren nach DWA-A 117 angewendet. Dafür ist ein statistischer Regen mit einer gewählten Dauer '''D''' und Häufigkeit '''n''' als Lastfall für die Bemessung heranzuziehen. Für die Ermittlung der Regenspende ist auf die „Starkniederschlagshöhen für Deutschland- KOSTRA“ (s. Beispiel Tabelle für einen Musterort) zurückzugreifen.
 
  
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
! Regendauer D !! r <sub>D(1)</sub> l/(s*ha) !! r <sub>D(0,2)</sub> l/(s*ha)
+
! Rain duration D !! r <sub>D(1)</sub> l/(sha) !! r <sub>D(0,2)</sub> l/(sha)
 
|-
 
|-
| 5 min || 135,0 || 243,0
+
| 5 min || 135.0 || 243.0
 
|-
 
|-
| 10 min || 113,0 || 183,9
+
| 10 min || 113.0 || 183.9
 
|-
 
|-
| 15 min || 97,2 || 152,6
+
| 15 min || 97.2 || 152.6
 
|-
 
|-
| 20 min || 85,3 || 131,7
+
| 20 min || 85.3 || 131.7
 
|-
 
|-
| 30 min || 69,5 ||104,8
+
| 30 min || 69.5 ||104.8
 
|-
 
|-
| 45 min || 52,9 || 81,2
+
| 45 min || 52.9 || 81.2
 
|-
 
|-
| 60 min || 43,1 || 66,8
+
| 60 min || 43.1 || 66.8
 
|-
 
|-
| 90 min || 32,3 || 49,7
+
| 90 min || 32.3 || 49.7
 
|-
 
|-
| 2 h || 26,4 || 40,3
+
| 2 h || 26.4 || 40.3
 
|-
 
|-
| 3 h || 19,8 || 29,9
+
| 3 h || 19.8 || 29.9
 
|-
 
|-
| 4 h || 16,1 || 24,3
+
| 4 h || 16.1 || 24.3
 
|-
 
|-
| 6 h || 12,1 || 18,0
+
| 6 h || 12.1 || 18.0
 
|-
 
|-
| 9 h || 9,1 || 13,4
+
| 9 h || 9.1 || 13.4
 
|-
 
|-
| 12 h || 7,4 || 10,9
+
| 12 h || 7.4 || 10.9
 
|-
 
|-
| 18 h || 5,4 || 7,9
+
| 18 h || 5.4 || 7.9
 
|-
 
|-
| 24 h || 4,3 || 6,5
+
| 24 h || 4.3 || 6.5
 
|-
 
|-
| 48 h || 2,6 || 3,7
+
| 48 h || 2.6 || 3.7
 
|-
 
|-
| 72 h || 2,1 || 2,9
+
| 72 h || 2.1 || 2.9
 
|}
 
|}
''KOSTRA Daten Musterort''
+
''KOSTRA data sample location''
  
===Zufluss zur Versickerungs- oder Retentionsanlage===
+
===Inflow to infiltration or retention systems===
  
 
:'''Q<sub>zu</sub> = 10<sup>-7</sup> x r<sub>D(n)</sub> x A<sub>red</sub> (1.)'''
 
:'''Q<sub>zu</sub> = 10<sup>-7</sup> x r<sub>D(n)</sub> x A<sub>red</sub> (1.)'''
Zeile 334: Zeile 332:
 
{|
 
{|
 
|-
 
|-
| Q<sub>zu</sub> || = Zufluss zur Versickerungsanlage in m³/s
+
| Q<sub>zu</sub> || = Inflow to infiltration system in m³/s
 
|-
 
|-
| r<sub>D(n)</sub> || = Regenspende der Dauerstufe D und Häufigkeit n [l/sha]
+
| r<sub>D(n)</sub> || = Rain yield for duration D and frequency n [L/sha]
 
|-
 
|-
| A<sub>red</sub> || = angeschlossene befestigte Fläche in m²
+
| A<sub>red</sub> || = connected paved areas in m²
 
|}
 
|}
  
===Ablauf aus der Versickerungsanlage===
+
===Discharge from the infiltration system===
  
Bei der Berechnung der Abflüsse aus einer Versickerungsanlage
+
Darcy’s Law is used to calculate the discharge from an infiltration system:
wird als Grundlage das Gesetz von Darcy herangezogen:
 
  
 
:'''Q<sub>s</sub> = (b+0,5h) x L x ½ x k<sub>f</sub> (2.a)'''
 
:'''Q<sub>s</sub> = (b+0,5h) x L x ½ x k<sub>f</sub> (2.a)'''
 
{|
 
{|
 
|-
 
|-
| k<sub>f</sub> || = Durchlässigkeitsbeiwert des gesättigten Bodens in m/s
+
| k<sub>f</sub> || = Permeability coefficient of the saturated soil in m/s
 
|-
 
|-
| b || = Sohlbreite der Rigole in m
+
| b || = Bottom width of the trench in m
 
|-
 
|-
| h || = Höhe der Rigole in m
+
| h || = Height of the trench in m
 
|-
 
|-
| L || = Länge der Rigole in m
+
| L || = Length of the trench in m
 
|}
 
|}
  
===Ablauf aus der Retentionsanlage===
+
===Discharge from the retention system===
  
:'''Q<sub>s</sub> = Q<sub>D</sub> (2.b)'''
+
===Continuity condition===
{|
 
|-
 
| Q<sub>D</sub> || = Drosselablauf im Falle einer Retentionsanlage
 
|}
 
 
 
===Kontinuitätsbedingung===
 
  
 
:'''V<sub>erf</sub> = L x b x h x s<sub>RR</sub> = (&sum;Q<sub>zu</sub> - &sum;Q<sub>s</sub>) x D x 60 (3.)'''  
 
:'''V<sub>erf</sub> = L x b x h x s<sub>RR</sub> = (&sum;Q<sub>zu</sub> - &sum;Q<sub>s</sub>) x D x 60 (3.)'''  
 
{|
 
{|
 
|-
 
|-
| V<sub>erf</sub> || = erforderliches Speichervolumen in m³
+
| V<sub>erf</sub> || = required storage volume in m³
 
|-
 
|-
| D || = Regendauer in min
+
| D || = Rain duration in min
 
|}
 
|}
''Versickerung:''
+
''Infiltration:''
Werden nun die Formeln 1. und 2.a in Formel 3. eingesetzt und nach L aufgelöst, ergibt sich die maßgebliche Rigolenlänge und das resultierende Rigolenvolumen.
+
If only formulas 1. and 2.a are used for formula 3 to calculate L, then this will result in a significant trench length and volume.
  
 
<math> = \dfrac {A_u \cdot 10^{-7} \cdot r_{D(n)}} {\tfrac {b_R \cdot h_R \cdot s_{RR}}{D \cdot 60 \cdot f_Z} + (b_R + \frac {h_R}{2}) \cdot \frac {k_f}{2}} </math>
 
<math> = \dfrac {A_u \cdot 10^{-7} \cdot r_{D(n)}} {\tfrac {b_R \cdot h_R \cdot s_{RR}}{D \cdot 60 \cdot f_Z} + (b_R + \frac {h_R}{2}) \cdot \frac {k_f}{2}} </math>
  
S<sub>RR</sub> = Speicherkoeffizient der Rigole
+
S<sub>RR</sub> = Storage coefficient of the trench
 +
 
 +
''Retention'':
 +
Here, only formulas 1. and 2.b are used in formula 3. V<sub>er</sub> = (&sum;Q<sub>zu</sub> - &sum;Q<sub>s</sub>) x D x 60'''
 +
The significant rain yield rD(n) of duration D and frequency n [L/s-ha] must be iteratively determined.
 +
 
 +
V<sub>er</sub> = (∑Q<sub>zu</sub> - ∑Q<sub>s</sub>) x D x 60
  
''Retention:''
+
The crucial rain yield rD(n), the duration D and frequency n [L/sha] must be determined iteratively.
Hier werden nun die Formeln 1. und 2.b in Formel 3 eingesetzt.
 
V<sub>er</sub> = (&sum;Q<sub>zu</sub> - &sum;Q<sub>s</sub>) x D x 60'''
 
Die maßgebliche Regenspende r D(n) der Dauerstufe D und Häufigkeit n [l/sha] muss iterativ bestimmt werden.
 
  
==Überstauhäufigkeit==
+
==Overflow frequency==
Für die rechnerische Ermittlung des Regenabflusses ist die anzunehmende Regenhäufigkeit der Regenspendenlinie von besonderer Bedeutung. Dieser Wert richtet sich nach der wirtschaftlichen Bedeutung des Gebietes und steht im Zusammenhang mit der Häufigkeit, mit der die geplante Anlage überstaut.
+
For statistical determination of rainwater outflows, the assumed frequency of rain from the rain yield curve is crucial. This value depends on the economic importance of the area and is related to the frequency with which the proposed system is congested.
  
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
! Häufigkeit der Bemessungsanlage (1-mal in n Jahren)!! Ort
+
! Frequency of dimensioning system (once in n years) !! Location
 
|-
 
|-
| 1 in 1 || Ländliche Gebiete
+
| 1 in 1 || Rural area
 
|-
 
|-
| 1 in 2 || Wohngebiete
+
| 1 in 2 || Residential area
 
|-
 
|-
| 1 in 2 || Stadtzentren, Industrie- und Gewerbegebiete mit Überflutungsprüfung
+
| 1 in 2 || City centers, industrial and commercial areas with flood assessment
 
|-
 
|-
| 1 in 5 || Stadtzentren, Industrie- und Gewerbegebiete ohne Überflutungsprüfung
+
| 1 in 5 || City centers, industrial and commercial areas without flood assessment
 
|-
 
|-
| 1 in 10 || Unterirdische Verkehrsanlagen, Unterführungen
+
| 1 in 10 || Underground traffic infrastructure, subways
 
|}
 
|}
  
Quelle: ATV A118
+
Source: ATV A118
  
==Überflutungsnachweis DIN 1986-100:2016-09 (Deutschland)==
+
==Flood verification DIN 1986-100:2016-09 (Germany)==
  
Entwässerungsanlagen für die Ableitung des Niederschlagswassers von kleinen Grundstücken können, soweit der Kanalnetzbetreiber keine anderen Vorgaben macht, ohne Überflutungsprüfung bemessen werden. Als klein gelten Grundstücke mit bis zu 800 m² abflusswirksamer Fläche, für die ein Anschlusskanal DN 150 ausreichend ist. Diese Regelung gilt sinngemäß auch für Versickerungsanlagen, die nach DWA-A 138 mit T = 5 a mit dem Berechnungsregen nach KOSTRA-DWD-2010 bemessen werden. Vorausgesetzt wird, dass auf Grund der Geländebeschaffenheit und architektonischer Gebäudeplanung kein Wasser bei Überstau der Anlage in das eigene Gebäude oder Nachbargebäude eindringen kann und behördlich keine anderen Regelungen bestehen.
+
Drainage systems for the discharge of precipitation water from small properties, so long as the sewer network provider has given no other guideline, without a more effective run-off surface, are sufficient for DN 150 connection to the sewer. The rule applies in the same sense to infiltration systems designed according to DWA-A 138 with T = 5 a and a dimensioning rainfall according to KOSTRA-DWD-2010. It is assumed that due to terrain condition and architectural building plans no backed-up water from the system will penetrate into the connected or neighbouring buildings and exceed any other official regulations.
  
Grundleitungen von Grundstücken nach DIN EN 752, d. h. bis 200 ha Ages bzw. bis etwa 60 ha AE,b, die größere schadlos überflutbare Hof-, Parkflächen oder andere Außenanlagen entwässern, können nach DWA-A 118:2006, Tabelle 4 bemessen werden. Dabei darf die Jährlichkeit des Berechnungsregens einmal in zwei Jahren nicht unterschritten werden.
+
Ground conduits from properties, according to DIN EN 752 from 200 ha A<sub>ges</sub> i.e. from approximately 60 ha A<sub>E,b</sub>, that drain larger, harmless flood-prone yard, park or other outdoor systems can be designed according to DWA-A 118:2006, Table 4. Here the yearly occurance of the dimensioning rainfall cannot be less once within two years.
  
Maßgebende kürzeste Regendauer in Abhängigkeit von mittlerer Geländeneigung und Befestigungsgrad:
+
Shortest normative rain period in relation to terrain slope and degree of sealing:
  
 
{| class="wikitable" style="text-align: center"
 
{| class="wikitable" style="text-align: center"
|<b>mittlere Gländeneigung</b>
+
|<b>average terrain slope</b>
|<b>Befestigung</b>
+
|<b>Sealing</b>
|<b>kürzeste Regendauer</b>
+
|<b>shortest rain period</b>
(nach dieser Norm r<sub>2</sub> in min)
+
(according to this norm r<sub>2</sub> in min)
 
|-
 
|-
 
|rowspan="2"|< 1%
 
|rowspan="2"|< 1%
Zeile 440: Zeile 434:
 
|}
 
|}
  
Quelle: DWA-A-118:2006, Tabelle 4
+
Source: DWA-A-118:2006, Table 4
  
Für die Differenz der auf der befestigten Fläche des Grundstücks anfallenden Regenwassermenge, V<sub>Rück</sub> (siehe Gleichung 20) in m3, zwischen dem mindestens 30-jährigen Regenereignis und dem 2-jährigen Berechnungsregen muss der Nachweis für eine schadlose Überflutung des Grundstücks erbracht werden. Ist ein außergewöhnliches Maß an Sicherheit erforderlich, ist eine Jährlichkeit des Berechnungsregens größer als 30 a zu wählen. Die unschädliche Überflutung kann auf der Fläche des eigenen Grundstückes, z. B. durch Hochborde oder Mulden, wenn keine Menschen, Tiere oder Sachgüter gefährdet sind, oder über andere Rückhalteräume, wie Rückhaltebecken, erfolgen, soweit die Niederschlagswasserableitung nicht auf andere Weise sichergestellt ist. Der nachfolgende Überflutungsnachweis ist in Abhängigkeit von den örtlichen Verhältnissen ggf. auch für Teile der Entwässerungsanlage (z. B. an den Entspannungspunkten) zu führen.
+
For the difference in the amount of rainwater accumulated on a sealed surface of a property, V<sub>Rück</sub> in m³ (see Equation 20), between the minimum 30-year rain event and the 2-year dimensioning rain, proof of harmless flooding on the property must be provided. If an exceptional level of safety is required, the yearly occurance of the dimensioning rain is chosen as greater than 30 a. The harmless flooding can take place on the property, e.g. with curbs or troughs, or through other retention areas, like retention basins, if people, animals or material goods are not endangered, so long as the precipitation water is not discharged on other fields. The following flood verification for guidance is dependent on the local conditions and if necessary for parts of the drainage system (e.g. in the calming areas).
  
===Gleichung 20===
+
===Equation 20===
  
'''V<sub>rück</sub> = ( r(D,30) x A<sub>ges</sub> – ( r(D,2) x C<sub>Dach</sub> + r(D,2) x A<sub>FaG</sub> x C<sub>FaG</sub>)) x D x 60 / (10000 x 1000)'''
+
'''V<sub>rück</sub> = (r(D,30) x A<sub>ges</sub> – ( r(D,2) x C<sub>Dach</sub> + r(D,2) x A<sub>FaG</sub> x C<sub>FaG</sub>)) x D x 60 / (10,000 x 1000)'''
  
V<sub>Rück</sub> die zurückzuhaltende Regenwassermenge, in m3
+
V<sub>Rück</sub> the to-be retained rainwater amount,
  
r<sub>(D,2)</sub> Regenereignis mit Dauerstufe D und 30-jähriger Wiederkehrzeit
+
r<sub>(D,2)</sub> rain event with period D and 30-year return time
  
D die kürzeste maßgebende Regendauer, in Minuten, für die Bemessung der Entwässerung außerhalb der Gebäude nach DWA-A118, Tabelle 4, sonst D = 5 Minuten
+
D the shortest normative rain period, min, for the dimensioning of drainage outside of a building according to DWA-A-118, Table 4, usually D = 5 min
  
C der Abflussbeiwert
+
C the run-off coefficient
  
A<sub>Dach</sub> die gesamte Gebäudedachfläche, in m²  
+
A<sub>Dach</sub> the total building roof area, m²  
  
A<sub>FaG</sub> die gesamte befestigte Fläche außerhalb der Gebäude, in m²  
+
A<sub>FaG</sub> the total sealed surface outside of the building, m²  
  
A<sub>ges</sub> die gesamte befestigte Fläche des Grundstücks, in m², d. h. A<sub>ges</sub> = A<sub>Dach</sub> + A<sub>FaG</sub>  
+
A<sub>ges</sub> the total sealed surface oft he property, m², hence A<sub>ges</sub> = A<sub>Dach</sub> + A<sub>FaG</sub>  
  
Sind die Grundleitungen nach DWA-A118:2006, Tabelle 4, bemessen, so kann statt des Bemessungsabflusses der – meist größere – maximale Abfluss der Grundleitungen bei Vollfüllung Q<sub>voll</sub> angesetzt werden nach Gleichung (21):
+
If the ground conduits are dimensioned according to DWA-A-118:2006, Table 4, then the dimensioning discharge, usually larger, instead can be set according to Equation (21) for the maximum discharge of the ground conduits at full charge Q<sub>voll</sub>:
  
===Gleichung 21===
+
===Equation 21===
  
'''V<sub>rück</sub> = (( r<sub>(D,30)</sub>) x A<sub>ges</sub>/ 1000)– Q<sub>voll</sub> x D x 60/1000'''
+
'''V<sub>rück</sub> = ((r<sub>(D,30)</sub>) x A<sub>ges</sub>/ 1000)– Q<sub>voll</sub> x D x 60/1000'''
  
V<sub>Rück</sub> die zurückzuhaltende Regenwassermenge, in
+
V<sub>Rück</sub> the to-be retained rainwater amount, m³
  
D D = 5, 10 und 15 Minuten. Der größte dieser drei Werte für V<sub>Rück</sub> ist maßgebend*  
+
D D = 5, 10 and 15 minutes. The larger of these three values is normative for V<sub>Rück</sub>*  
  
Q<sub>voll</sub> max. Abfluss der Grundleitungen bei Vollfüllung in l/s  
+
Q<sub>voll</sub> max. discharge of the ground conduits at full charge, L/s  
  
A<sub>ges</sub> die gesamte befestigte Fläche des Grundstücks, in m², d. h. A<sub>ges</sub> = A<sub>Dach</sub> + A<sub>FaG</sub>
+
A<sub>ges</sub> the total sealed surface of the property, m², hence A<sub>ges</sub> = A<sub>Dach</sub> + A<sub>FaG</sub>
  
Sollten die Regeneinzugsflächen des Grundstücks weitgehend aus Dachflächen und nicht schadlos überflutbaren Flächen (z. B. > 70 %, hierzu zählen auch Innenhöfe) bestehen, ist die Überflutungsprüfung in Verbindung mit der Notentwässerung für das 5-Minuten Regenereignis in 100 Jahren nachzuweisen (r<sub>(5,100)</sub>).  
+
Should the rain catchment surfaces of the property be mostly roof areas and not harmless, flood-prone surfaces (e.g. > 70 %, here as well inner courtyards), the flood verification is demonstrated in connection with emergency drainage of a 5-min, 100-year rain event (r<sub>(5,100)</sub>).  
  
Für den Fall der Begrenzung der Einleitung ist zusätzlich zum Überflutungsnachweis die Berechnung des erforderlichen Rückhaltevolumens (Regenrückhalteraum (RRR)) entsprechend DWA-A 117 mit dem „einfachen Verfahren“ durchzuführen. Hierbei wird vereinfachend vorausgesetzt, dass die Jährlichkeit ''T'' des Berechnungsregens (einheitlich bezogen auf die gesamte abflusswirksame Fläche des Grundstücks), der der zulässigen Überschreitungshäufigkeit des RRR entspricht. Die Einleitungsbeschränkung muss den Drosselabfluss in l/s und die Jährlichkeit ''T'' der zulässigen Überschreitung enthalten.  
+
In the case of limited loading, in addition to the flood verification, the calculation of the required retention volume (Rain Retention Area (RRA)) must be carried out with the „simplest procedure“ in accordance with DWA-A 117. For simplicity’s sake, it is assumed that the yearly occurance T of the dimensioning rain (uniform in relation to the total effective property area) corresponds to the permissible exceedance frequency of the RRA. The loading restriction must include the throttle discharge, L/s and the yearly occurance T of the permitted excess.
Für die Berechnung volumenbezogener Bemessungsaufgaben, wie die Bemessung von Niederschlagswasserrückhalteräumen, sind für die Ermittlung der abflusswirksamen Fläche mittlere Abflussbeiwerte C<sub>m</sub> nach Tabelle 9 zu verwenden.  
+
For the calculation of volume related dimensioning exercises, such as the dimensioning of precipitation water retention areas, the mean discharge coefficients C<sub>m</sub> according to Table 9 are to be used to determine the effective area.
Für die Dimensionierung des Regenrückhalteraums müssen entsprechend DWA-A 117:2013 die zum Entwässerungssystem gelangenden Abflüsse sowohl von der befestigten Fläche A<sub>E,b</sub> als auch von einer nicht befestigten Fläche (Tabelle 9, Nr. 3) mit Zufluss zu einem Ablauf in die Entwässerungsanlage berücksichtigt werden. Die ermittelten Flächenarten werden in dieser Norm vereinfachend als A<sub>FaG</sub> bezeichnet, mit den mittleren Abflussbeiwerten C<sub>m</sub> multipliziert und zu einem Rechenwert Au zusammengefasst.  
+
The dimensioning of rain retention areas must considered according to DWA-A 117:2013 for the run-off entering the drainage system in relation to both the sealed area A<sub>E,b</sub> as well as from the non-sealed area (Table 9, No. 3) from inlet to outlet in the drainage system. The determined surface types will be simply called A<sub>FaG</sub> in this norm, with the mean run-off coefficients C<sub>m</sub> multiplied and linked to the calculated value A<sub>u</sub>.
Das erforderliche Speichervolumen V<sub>RRR</sub> wird aus der maximalen Differenz der in einem Zeitraum gefallenen Niederschlagsmenge und dem in diesem Zeitraum über die Drossel weitergeleiteten Abflussvolumen ermittelt.  
+
The required storage volume V<sub>RRR</sub> will be determined according to the maximum difference between the rainfall amount and the discharge volume through the throttle in a specific time period.  
  
In Anknüpfung an DWA-A 117 gilt für Grundstücksentwässerungsanlagen für die Bemessung des Rückhalteraumes (RRR) Gleichung (22).
+
In accordance with DWA-A 117, Equation (22) applies for property drainage systems for the design of retention areas (RRA).
  
===Gleichung 22===
+
===Equation 22===
  
'''V<sub>RRR</sub> = A<sub>u</sub> x r<sub>D,T</sub> / 10000 x D x F<sub>z</sub> x 0,06 – D x f<sub>z</sub> x Q<sub>Dr</sub> x 0,06'''
+
'''V<sub>RRA</sub> = A<sub>u</sub> x r<sub>D,T</sub> / 10,000 x D x F<sub>z</sub> x 0.06 – D x f<sub>z</sub> x Q<sub>Dr</sub> x 0.06'''
  
Die Gleichung 22 entspricht der Berechnung des erforderlichen Rückhaltevolumens auf der Basis einer Einleitbeschränkung entsprechend DWA-A 117 mit dem „einfachen Verfahren“ (Formel s. Kapitel 3.2 Drosselabfluss).
+
Equation 22 cooresponds to the calculation of the required retention volume related to the inlet restriction according to DWA-A 117 using the „simple method“ (see Capital 3.2 [[#Throttle_discharge|Throttle discharge]] for formula).
  
===Beispielrechnung zurückzuhaltende Regenwassermenge nach Überflutungsnachweis===
+
===Example calculation to-be retained rainwater amount according to flood verification===
  
Standort: Aachen Angeschlossene Auffangflächen: Gebäudedachflächen: A<sub>Dach</sub> = 1.250 m², Schrägdach Ziegel, C<sub>Dach</sub> = 0,8 Auffangflächen außerhalb von Gebäuden: A<sub>FaG</sub> = 4.445 m², Asphalt, C<sub>FaG</sub> = 0,9 Gesamte befestigte Fläche des Grundstückes: A<sub>ges</sub> = 5.695 m² (A<sub>red</sub> = 5.000 m²) Mittlere Geländeneigung: < 1% Befestigung: > 50 %  
+
Location: Aachen Connected catchment surfaces: Building surfaces: A<sub>Dach</sub> = 1,250 m², pitched tiled roof C<sub>Dach</sub> = 0.8 Catchment surfaces outside of the building: A<sub>FaG</sub> = 4,445 m², asphalt, C<sub>FaG</sub> = 0.9 Total sealed surface of the property: A<sub>ges</sub> = 5,695 m² (A<sub>red</sub> = 5,000 m²) Medium terrain slope: < 1% sealing: > 50 %  
  
====Berechnung nach Gleichung 20====
+
====Calculation according to Equation 20====
  
V<sub>rück</sub> = ( r<sub>(D,30)</sub> x A<sub>ges</sub> – ( r<sub>(D,2)</sub> x C<sub>Dach</sub> + r<sub>(D,2)</sub> x A<sub>FaG</sub> x C<sub>FaG</sub>)) x D x 60 / (10000 x 1000)
+
V<sub>rück</sub> = (r<sub>(D,30)</sub> x A<sub>ges</sub> – (r<sub>(D,2)</sub> x C<sub>Dach</sub> + r<sub>(D,2)</sub> x A<sub>FaG</sub> x C<sub>FaG</sub>)) x D x 60 / (10000 x 1000)
 
   
 
   
mit: D = 10 Min (aus DWA-A-118:2006, Tabelle 4)  
+
with: D = 10 Min (from DWA-A-118:2006, Table 4)  
  
r<sub>(D,30)</sub> = 273 l/sxha r<sub>(D,2)</sub> = 148 l/sxha V<sub>rück</sub> = 273 x 5.695 – (148 x 1.250 x 0,8 + 148 x 4.445 x 0,9) x 10 x 60 / (10000 x 1000) = 48,9 m³
+
r<sub>(D,30)</sub> = 273 L/sha r<sub>(D,2)</sub> = 148 L/sha V<sub>rück</sub> = 273 x 5,695 – (148 x 1,250 x 0.8 + 148 x 4,445 x 0.9) x 10 x 60 / (10,000 x 1000) = 48.9 m³
  
====Berechnung nach Gleichung 21====
+
====Calculation according to Equation 21====
  
V<sub>rück</sub> = (( r<sub>(D,30)</sub> x A<sub>ges</sub> / 10000) – Q<sub>voll</sub>) x D x 60 /1000  
+
V<sub>rück</sub> = ((r<sub>(D,30)</sub> x A<sub>ges</sub> / 10,000) – Q<sub>voll</sub>) x D x 60 /1000  
  
mit: Einzelnachweis der Bemessungsregenspenden:  
+
With: single verification of the dimensioning rainfall quantity:  
  
a) r<sub>(5,30)</sub> =377 l/sxha (aus DIN 1986-100 Tabelle A.1 Regenspenden in Deutschland)  
+
a) r<sub>(5.30)</sub> = 377 L/sha (from DIN 1986-100, Table A.1 Rain Quantity in Germany)  
  
b) r<sub>(10,30)</sub> = 273 l/sxha
+
b) r<sub>(10.30)</sub> = 273 L/sha
  
c) r<sub>(15,30)</sub> = 223 l/sxha Q<sub>voll</sub> = 100,0 l/s  
+
c) r<sub>(15.30)</sub> = 223 L/sha Q<sub>voll</sub> = 100.0 L/s  
  
a) V<sub>rück</sub> = ((377 x 5.695 / 10000) – 100,0 ) x 5 x 60 / 1000 = 34,4 m³  
+
a) V<sub>rück</sub> = ((377 x 5,695 / 10,000) – 100.0) x 5 x 60 / 1000 = 34.4 m³  
  
b) V<sub>rück</sub> = ((273 x 5.695 / 10000) – 100,0 ) x 10 x 60 / 1000 = 33,3 m³  
+
b) V<sub>rück</sub> = ((273 x 5,695 / 10,000) – 100.0 ) x 10 x 60 / 1000 = 33.3 m³  
  
c) V<sub>rück</sub> = ((223 x 5.695 / 10000) – 100,0 ) x 15 x 60 / 1000 = 24,3 m³
+
c) V<sub>rück</sub> = ((223 x 5,695 / 10,000) – 100.0 ) x 15 x 60 / 1000 = 24.3 m³
  
Der größte der drei Werte für Vrück ist maßgebend.
+
The larger of the three values V<sub>rück</sub> is normative.
  
====Berechnung nach Gleichung 22====
+
====Calculation according to Equation 22====
  
Das Einstauvolumen aus der Regelbemessung (nach Einleitbeschränkung) ergibt sich nach Kap. [[#Berechnungsbeispiel_erforderliches_Speichervolumen|3.2.4]] zu 41,8 m³.
+
The impounding volume from the standard calculation (according to the inlet limitation) results from Cap. [[#Calculation_example_of_required_storage_volume|3.2.4]] as 41.8 m³.
  
====Fazit:====
+
====Conclusion:====
  
Das sich aus den Berechnungen für den Überflutungsnachweis und für die Einleitungsbeschränkung ergebende größere Volumen ist maßgebend. Die maßgebende Größe des Rückhalteraumes ergibt sich somit nach Gleichung 18 zu 48,9 m³. Somit wird durch den Überflutungsnachweis das erforderliche Rückhaltevolumen um 7,1 m³ (17 %) erhöht. Spätestens dann, wenn das Überflutungsvolumen oberflächig nicht dargestellt werden kann, müssen unterirdische Speichervolumen größer ausgelegt werden.
+
This resulting larger volume is relevant for the calculations for flood verification and the inlet limitation. The relevant size of the retention space is calculated from Equation 18 as 48.9 m³. With this based on the flood verification, the required retention volume is increased by 7.1 m³ (17%). At the latest when the flood volume cannot be represented on the surface then the underground storage volumes must be constructed larger.
  
==Beispielberechnungen Versickerung mit DRAINMAX Tunnel==
+
==Sample calculations for infiltration with DRAINMAX Tunnel==
  
''a) nur mit dem Wert 15 /0,2 = Beispiel für viele Gebiete im Ausland''
+
''a) with value D = 15min and n = 0.2 = Example for various international regions''
  
:Standort: Aachen
+
:Location: Aachen
:A<sub>red</sub> = 100 m²
+
:A<sub>red</sub>= 100 m²
:Bemessungsregen: r<sub>15,n=0,2</sub> = 152,6 l/(s*ha)
+
:Measured rainfall: r15,n=0.2 = 152.6 L/(sha)
:k<sub>f</sub> = 1*10<sup>-4</sup> m/s (Mittelsand)
+
:k<sub>f</sub> = 1*10-4 m/s (medium sand)
:s<sub>rr</sub> = 0,56 (DRAINMAX Tunnel Einbau nach DIBt)
+
:s<sub>rr</sub> = 0.56 (DRAINMAX Tunnel installation according to German Institute for Civil Engineering)
:f<sub>z</sub> = 1,1
+
:f<sub>z</sub> = 1.1
  
''Beispielberechnung für INTEWA DRAINMAX Tunnel im Kiesblock:''
+
''Sample calculation for INTEWA DRAINMAX Tunnel in gravel bed:''
  
:B = 1,85 m, H = 1 m,  L = 2,25 m
+
:B = 1.85 m, H = 1 m,  L = 2.25 m
:L<sub>erf,rigole</sub> = 1,31 m
+
:L<sub>erf,rigole</sub> = 1.31 m
:V<sub>erf,rigole</sub> = 1,36 m³ (= B x H x L<sub>erf,rigole</sub> x s<sub>rr</sub> = 1,85 m x 1 m x 1,31 m x 0,56)
+
:V<sub>erf,rigole</sub> = 1.36 m³ (= B x H x L<sub>erf,rigole</sub> x s<sub>rr</sub> = 1.85 m x 1 m x 1.31 m x 0.56)
:Erforderliche Anzahl DRAINMAX Tunnel: LL<sub>erf,rigole</sub> / L = 0,82
+
:Required number of DRAINMAX Tunnels: LL<sub>erf,rigole</sub> / L = 0.82
  
''b) Mit Iteration = Beispiel für Deutschland''
+
''b) With iteration = Example for Germany''
  
:Standort: Aachen
+
:Location: Aachen
 
:A<sub>red</sub> = 100 m²
 
:A<sub>red</sub> = 100 m²
:Bemessungsregen: r<sub>15,n=0,2</sub> = 152,6 l/(s*ha)
+
:Measured rainfall: r<sub>15, n=0.2</sub> = 152.6 l/(s*ha)
:k<sub>f</sub> = 1*10<sup>-4</sup> m/s (Mittelsand)  
+
:k<sub>f</sub> = 1*10<sup>-4</sup> m/s (medium sand)  
  
 
{| class="wikitable" "text-align:rechts"
 
{| class="wikitable" "text-align:rechts"
 
|-
 
|-
! Dauer D [min] !! Regenspende r [l/sha] !! L<sub>erf,rigole</sub> [m] !! V<sub>erf,rigole</sub> [m³]
+
! Duration D [min] !! Rain yeld r [L/sha] !! L<sub>erf,rigole</sub> [m] !! V<sub>erf,rigole</sub> [m³]
 
|-
 
|-
| 5 || 243,00 || 0,75 || 0,77
+
| 5 || 243.00 || 0.75 || 0.77
 
|-
 
|-
| 10 || 183,90 || 1,09 || 1,13
+
| 10 || 183.90 || 1.09 || 1.13
 
|-
 
|-
| 15 || 152,60 || 1,31 || 1,36
+
| 15 || 152.60 || 1.31 || 1.36
 
|-
 
|-
| 20 || 131,70 || 1,46 || 1,51
+
| 20 || 131.70 || 1.46 || 1.51
 
|-
 
|-
| 30 || 104,80 || 1,64 || 1,69
+
| 30 || 104.80 || 1.64 || 1.69
 
|-
 
|-
| 45 || 81,20 || 1,74 || 1,80
+
| 45 || 81.20 || 1.74 || 1.80
 
|-
 
|-
| '''60''' || '''66,80''' || '''1,76''' || '''1,83'''
+
| '''60''' || '''66.80''' || '''1.76''' || '''1.83'''
 
|-
 
|-
| 90 || 49,70 || 1,70 || 1,76
+
| 90 || 49.70 || 1.70 || 1.76
 
|-
 
|-
| 120 || 40,30 || 1,62 || 1,68
+
| 120 || 40.30 || 1.62 || 1.68
 
|-
 
|-
| 180 || 29,90 || 1,46 || 1,51
+
| 180 || 29.90 || 1.46 || 1.51
 
|-
 
|-
| 240 || 24,30 || 1,33 || 1,38
+
| 240 || 24.30 || 1.33 || 1.38
 
|-
 
|-
| 360 || 18,00 || 1,12 || 1,16
+
| 360 || 18.00 || 1.12 || 1.16
 
|-
 
|-
| 540 || 13,40|| 0,91 || 0,95
+
| 540 || 13.40|| 0.91 || 0.95
 
|-
 
|-
| 720 || 10,90 || 0,78 || 0,81
+
| 720 || 10.90 || 0.78 || 0.81
 
|-
 
|-
| 1080 || 7,90 || 0,60 || 0,62
+
| 1080 || 7.90 || 0.60 || 0.62
 
|-
 
|-
| 1440 || 6,50 || 0,51 || 0,52
+
| 1440 || 6.50 || 0.51 || 0.52
 
|-
 
|-
| 2880 || 3,70 || 0,3 || 0,31
+
| 2880 || 3.70 || 0.3 || 0.31
 
|-
 
|-
| 4320 || 2,90 || 0,24 || 0,25
+
| 4320 || 2.90 || 0.24 || 0.25
 
|}
 
|}
  
''c. Tabelle zur Grobabschätzung für kleine Anlagen mit r<sub>15,n=0,2</sub>''
+
''c. Table for rough estimation of small systems with r<sub>15,n=0.2</sub>''
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
! k<sub>f</sub> (m/s) !! !! colspan="3"| z.B. Standort Aachen (D) r<sub>15,0,2</sub>=152,6 l/(s*ha)!! colspan="3"|z.B. Standort Berlin (D) r<sub>15,0,2</sub>=213,1 l/(s*ha)
+
! k<sub>f</sub> (m/s) !! !! colspan="3"| e.g. location Aachen (D) r<sub>15,0.2</sub>=152.6 L/sha!! colspan="3"|e.g. location Berlin (D) r<sub>15,0.2</sub>=213.1 L/sha
 
|-
 
|-
 
| ||  || A=100 m<sup>2</sup> || A=150 m<sup>2</sup> || A=200 m<sup>2</sup> || A=100 m<sup>2</sup> || A=150 m<sup>2</sub> || A=200 m<sup>2</sup>
 
| ||  || A=100 m<sup>2</sup> || A=150 m<sup>2</sup> || A=200 m<sup>2</sup> || A=100 m<sup>2</sup> || A=150 m<sup>2</sub> || A=200 m<sup>2</sup>
 
|-
 
|-
| 1*10<sup>-4</sup> || Volumen in m<sup>3</sup> || 1,36 || 2,04 || 2,72 || 1,90 || 2,85 || 3,79
+
| 1*10<sup>-4</sup> || Volume in m<sup>3</sup> || 1.36 || 2.04 || 2.72 || 1.90 || 2.85 || 3.79
 
|-
 
|-
| 1*10<sup>-5</sup> || Volumen in m<sup>3</sup> || 1,49 || 2,24 || 2,99 || 2,09 || 3,13 || 4,79
+
| 1*10<sup>-5</sup> || Volume in m<sup>3</sup> || 1.49 || 2.24 || 2.99 || 2.09 || 3.13 || 4.79
 
|-
 
|-
| 1*10<sup>-6</sup> || Volumen in m<sup>3</sup> || 1,51 || 2,26 || 3,02 || 2,11 || 3,16 || 4,21
+
| 1*10<sup>-6</sup> || Volume in m<sup>3</sup> || 1.51 || 2.26 || 3.02 || 2.11 || 3.16 || 4.21
 
|}
 
|}
  
==Grobabschätzung des Retentionsvolumens==
+
==Rough estimation of retention volume==
  
Für eine grobe Abschätzung des erforderlichen Retentionsvolumens bei vorgegebener Regendauer kann das folgende Bemessungsverfahren verwendet werden.
+
The following method of calculation can be used for a rough estimation of required retention volume with specified rain duration.
  
'''Beispielrechnung:'''
+
'''Example calculation:'''
  
:Zulässiger Abfluss des Grundstückes: 1,5 l/s x ha
+
:Permitted discharge from property: 1.5 L/sha
:Grundstücksgröße: 0,105 ha
+
:Property size: 0.105 ha
:Regenspende r<sub>15(1)</sub> = 108 l/s x ha
+
:Rain yield r<sub>15(1)</sub> = 108 L/sha
:Regenspende r<sub>15(2)</sub> = 193 l/s x ha
+
:Rain yield r<sub>15(2)</sub> = 193 L/sha
  
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
! Fläche !! x !! Abflussbeiwert !! x !! Regenspende !!= !! Q<sub>r15(2)</sub>
+
! Surface !! x !! Runoff coefficient !! x !! Rain yield !!= !! Q<sub>r15(2)</sub>
 
|-
 
|-
| 231 m<sup>2</sup> || x || 1 || x || 0,0193 l/s x m<sup>2</sup> || = || 4,46 l/s
+
| 231 m<sup>2</sup> || x || 1 || x || 0.0193 L/s x m<sup>2</sup> || = || 4.46 L/s
 
|-
 
|-
| 114 m<sup>2</sup> || x || 0,8 || x || 0,0193 l/s x m<sup>2</sup> || = || 1,76 l/s
+
| 114 m<sup>2</sup> || x || 0.8 || x || 0.0193 L/s x m<sup>2</sup> || = || 1.76 L/s
 
|-
 
|-
| Summen Regenwasserabfluss || || || ||Q<sub>rges</sub> || = || 6,22 l/s
+
| Total rainwater runoff || || || ||Q<sub>rges</sub> || = || 6.22 L/s
 
|-
 
|-
 
|
 
|
 
|-
 
|-
| colspan="2"|Zulässige Einleitungsmenge: || Q<sub>ab</sub> ||=|| colspan="3"|0,105 ha (Grundstücksgröße) x 1,5 l/s x ha
+
| colspan="2"| Approved discharge quantity: || Q<sub>ab</sub> ||=|| colspan="3"|0.105 ha (property size) x 1.5 L/sha
 
|-
 
|-
| colspan="3"| || = || colspan="3"|0,158 l/s
+
| colspan="3"| || = || colspan="3"|0.158 L/s
 
|-
 
|-
| colspan="2"|Rückzuhaltende Regenwassermenge: || Q<sub>s</sub> ||=|| colspan="3"|Q<sub>r15(0,2)ges</sub> - Q<sub>ab</sub>
+
| colspan="2"|Rainwater quantity for retention: || Q<sub>s</sub> ||=|| colspan="3"|Q<sub>r15(0.2)ges</sub> - Q<sub>ab</sub>
 
|-
 
|-
| colspan="3"| || = || colspan="3"|6,22 l/s – 0,158 l/s = 6,06 l/s
+
| colspan="3"| || = || colspan="3"|6.22 L/s – 0.158 L/s = 6.06 L/s
 
|-
 
|-
 
|
 
|
 
|-
 
|-
| colspan="7"| Erforderliches Rückstauvolumen Verf: (Die Rückhalteanlage muss Qs für 15 Min. aufnehmen).
+
| colspan="7"| Required backwater volume Verf: (The retention system must absorb Qs for 15 min.).
 
|-
 
|-
 
| Verf ||colspan="6" |= Q<sub>s</sub> x 60 x 15 = Q<sub>s</sub> x 900  
 
| Verf ||colspan="6" |= Q<sub>s</sub> x 60 x 15 = Q<sub>s</sub> x 900  
 
|-
 
|-
| || colspan="6" |=  6,06 l/s x 900 s = 5,5 m<sup>3</sup>
+
| || colspan="6" |=  6.06 L/s x 900 s = 5.5 m<sup>3</sup>
 
|}
 
|}
  
==Genaue Bemessung einer Rigole oder Retentionsanlage mit Planungssoftware==
+
==Accurate dimensioning of a trench or retention system with planning software==
Da eine Berechnung des erforderlichen Rigolenvolumens iterativ erfolgt, ist sie am geeignetsten mit einer Planungssoftware wie dem [https://www.rainplaner.net/de/ RAINPLANER] durchzuführen.
+
Since calculation of the required trench volume is iterative, planning software such as the [https://www.rainplaner.net/en/ RAINPLANER] is better designed for solving it.
  
==Bemessung einer Flächenversickerung==
+
==Dimensioning surface infiltration==
  
  
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
! colspan="2"|A<sub>s</sub> = A<sub>red</sub> / ( k<sub>r</sub> x s<sub>f</sub> x 107 / 2 x r <sub>D(n)</sub> –1)  
+
! colspan="2"|A<sub>s</sub> = A<sub>red</sub> / (k<sub>r</sub> x s<sub>f</sub> x 107 / 2 x r <sub>D(n)</sub> –1)  
 
|-
 
|-
| A<sub>red</sub> || = angeschlossene befestigte Fläche
+
| A<sub>red</sub> || = connected paved surfaces
 
|-
 
|-
| s<sub>f</sub> || = Fugenanteil einer durchlässigen Flächenbefestigung (0 < s<sub>f</sub> =< 1)
+
| s<sub>f</sub> || = Joints proportion in a permeable paved area (0 < s<sub>f</sub> =< 1)
 
|-
 
|-
| k<sub>r</sub> || = Durchlässigkeitsbeiwert in der betrachteten Versickerungsebene
+
| k<sub>r</sub> || = Permeability coefficient in the considered infiltration layer
 
|-
 
|-
| r<sub>D(n)</sub> || = maßgebende Regenspende
+
| r<sub>D(n)</sub> || = Rain yield
 
|-
 
|-
 
|
 
|
 
|-
 
|-
!colspan="2"|Beispiel:
+
!colspan="2"|Example:
 
|-
 
|-
 
| A<sub>red</sub> || = 300 m<sup>2</sup>
 
| A<sub>red</sub> || = 300 m<sup>2</sup>
 
|-
 
|-
| s<sub>f</sub> || = 1 (INTEWA Rasengitterplatten)
+
| s<sub>f</sub> || = 1 (INTEWA grass grid pavers)
 
|-
 
|-
 
| k<sub>r</sub> || = 2 x 10<sup>-4</sup> m/s  
 
| k<sub>r</sub> || = 2 x 10<sup>-4</sup> m/s  
 
|-
 
|-
| r <sub>D(n)</sub> || = aus KOSTRA Tabelle bei n=0,2/a und D=10 min: r<sub>10(0,2)</sub> = 204,60l/s ha
+
| r <sub>D(n)</sub> || = from KOSTRA table with n=0.2/a and D=10 min: r<sub>10(0.2)</sub> = 204.60 L/sha
 
|-
 
|-
 
|
 
|
 
|-
 
|-
!colspan="2"|A<sub>s</sub> = 300 / ( 2 x 10<sup>-4</sup> x 1 x 10<sup>7</sup> / 2 x 204,6 –1) = 77 m<sup>2</sup>
+
!colspan="2"|A<sub>s</sub> = 300 / ( 2 x 10<sup>-4</sup> x 1 x 10<sup>7</sup> / 2 x 204.6 –1) = 77 m<sup>2</sup>
 
|}
 
|}
  
==Bemessung von Versickerungs - Rigolen hinter Kleinklärsystemen==
+
==Dimensioning infiltration trenches behind small wastewater treatment systems==
  
Nach DIN 4261-1, Stand 2002, kann das Ablaufwasser von Kleinkläranlagen bei Böden mit k<sub>f</sub> = 5 x 10<sup>-7</sup> bis 5 x 10<sup>-3</sup> m/s über eine Rigole versickert werden. Da sich die Sohlen der Versickerungsanlagen mit der Zeit zusetzen können, sind auf Dauer nur die Seitenflächen wirksam. Um unterschiedliche Versickerungsleistung z.B. bei Frost oder ungleichmäßige Beschickung der Rigole zu puffern ist ein großes Retentionsvolumen von Vorteil, wie es der Tunnel z.B. bietet. Nach der DIN gelten folgende vereinfachte Bemessungsmethoden:  
+
According to DIN 4261-1, version 2002, the water discharged from SWWTPs can be infiltrated through trenches in soils with k<sub>f</sub> = 5 x 10<sup>-7</sup> to 5 x 10<sup>-3</sup> m/s. As the base of infiltration system can clog up with time, only the side areas remain effective in the long run. A large retention volume is an advantage for variable infiltration efficiency i.e. during frost or uneven loading of the trench. The following simplified dimensioning methods shall apply according to DIN:  
  
  
[[Datei:RWV_rigolenKleinkl.jpg |miniatur|400px|Rigolen hinter Kleinklärsystemen]]
+
[[Datei:RWV_rigolenKleinkl.jpg|miniatur|400px|Trenches behind small wastewater treatment systems]]
 
{| class="wikitable"
 
{| class="wikitable"
 
|-
 
|-
! colspan="3"| Erforderliche Wandfläche (m<sup>2</sup>/Einwohnerwerte EW):
+
! colspan="3"| Required wall area (m<sup>2</sup>/inhabitant value PE):
 
|-
 
|-
| colspan="2"|1 m<sup>2</sup> / EW bis 1,5 m<sup>2</sup> / EW bei:|| Sand-Kiesgemische, Sande, schwach schluffige Sande
+
| colspan="2"|1 m<sup>2</sup> / PE to 1.5 m<sup>2</sup> / PE with:|| Sand-gravel mixture, sand, light silty sand
 
|-
 
|-
| colspan="2"|2 m<sup>2</sup> / EW bis 2,5 m<sup>2</sup> / EW bei:|| Schluffe (auch schwach tonig), Sand-Schluffmischungen, Stein-Lehmgemische
+
| colspan="2"|2 m<sup>2</sup> / PE to 2.5 m<sup>2</sup> / PE with:|| Silt (also light clay), sand-silt mixture, stone-loam mixture
 
|-
 
|-
! colspan="3"|  Erforderliche Anzahl am Beispiel der DRAINMAX Tunnel:
+
! colspan="3"|  Required number for example of DRAINMAX Tunnel:
 
|-
 
|-
| Grundelement|| colspan="2"|2,25 m Länge x 0,8 m Höhe x 2 Seiten
+
| Base element || colspan="2"|2.25 m length x 0.8 m heigth x 2 sides
 
|-
 
|-
| A<sub>s</sub> ||colspan="2"|= 3,6 m<sup>2</sup> je Tunnel ohne Stirnseiten
+
| A<sub>s</sub> ||colspan="2"|= 3.6 m<sup>2</sup> per tunnel without front walls
 
|-
 
|-
 
|
 
|
 
|-
 
|-
|EW || bis 1,5 m²/EW || bis 2,5 m²/EW
+
|PE|| to 1.5 m²/PE || to 2.5 m²/PE
 
|-
 
|-
|4 || 1 Stk.|| 2 Stk.
+
|4 || 1 pcs.|| 2 pcs.
 
|-
 
|-
|8 || 1 Stk.|| 4 Stk.
+
|8 || 1 pcs.|| 4 pcs.
 
|-
 
|-
|12|| 3 Stk.|| 6 Stk.
+
|12|| 3 pcs.|| 6 pcs.
 
|-
 
|-
|16 || 4 Stk.|| 8 Stk.
+
|16 || 4 pcs.|| 8 pcs.
 
|}
 
|}
Bei anderen Bodenverhältnissen und höheren EW-Werten sollte eine Berechnung durchgeführt werden.
+
A specified calculation must be done with other soil conditions and higher PE values.
  
  
'''Vergleich DRAINMAX Tunnel gegenüber Rohrrigolenvariante'''
+
'''Comparison between DRAINMAX Tunnel and pipe trench variants'''
  
Laut EN 12566-3 für Kleinkläranlagen (KKA) fallen 150 l/Tag und Einwohner (EW) mit folgender Tagesverteilung an:
+
According to EN 12566-3 for small wastewater treatment plants (SWWTPs) 150 L / day / inhabitant (PE) has the following daily distribution:
  
 
3h = 30%<br/>
 
3h = 30%<br/>
Zeile 732: Zeile 726:
 
7h = 0%<br/>
 
7h = 0%<br/>
  
Bei Verwendung einer klassischen ''Rohrrigole'' ist der größte Volumenstrom zu ermitteln. Dieser  entsteht innerhalb von 2h mit 40%. Bei einer KKA mit 5 EW errechnet dieser sich wie folgt:
+
When using a classic pipe trench, the largest flow rate must be determined. This occurs within 2h with 40%. For a SWWTP with 5 PE this is calculated as follows:
  
40 % in 2 h von 750 l/Tag<br/>
+
40 % in 2 h from 750 L/day<br/>
=> 300 l/2h<br/>
+
=> 300 L/2h<br/>
=> 0,0417 l/s<br/>
+
=> 0.0417 L/s<br/>
  
Bei der Verwendung des ''DRAINMAX Tunnels'' kann das Tagesvolumen in der Rigole gespeichert werden. Der größte Volumenstrom errechnet sich dann wie folgt:
+
When using the DRAINMAX Tunnel, the daily volume can be stored in the trench. The largest flow rate is then calculated as follows:
  
100 % in 24 h von 750 l/Tag<br/>
+
100 % in 24 h from 750 L/day<br/>
=> 750 l/24 h<br/>
+
=> 750 L/24 h<br/>
=> 0,0087 l/s<br/>
+
=> 0.0087 L/s<br/>
  
=> dieser Volumenstrom ist 4,8 mal kleiner als bei der Rohrrigolenvariante<br/>
+
=> this flow rate is 4.8 times smaller than with the pipe trench variant<br/>
=> die DRAINMAX Rigole kann ungefähr 4,8 mal kleiner dimensioniert werden als die Rohrrigole<br/>
+
=> the DRAINMAX tunnel can be dimensioned approx. 4.8 times smaller than the pipe trench<br/>
 
<br/>
 
<br/>
  
=Rechtliche Rahmenbedingungen in Deutschland=
+
=Legal framework conditions in Germany=
Bei der Planung und Installation einer Versickerungs- oder Rückhalteanlage sind unter anderem die aktuellen Fassungen folgender Regelungen zu beachten:
+
When planning and installing an infiltration or retention system, the current versions of the following regulations must be observed:
  
 
{| class="wikitable" style="text-align:rechts"
 
{| class="wikitable" style="text-align:rechts"
 
|-
 
|-
! Regelungsbereich !! Regelwerk !! Inhalt
+
! Scope !! Policy !! Content
 
|-
 
|-
| rowspan="9" | '''Wasserversorgung'''  
+
| rowspan="9" | '''Water supply'''  
| Arbeitsblatt DWA-A 138 || Planung, Bau und Betrieb von Anlagen zur Versickerung von Niederschlagswasser
+
| Arbeitsblatt DWA-A 138 || Planning, construction and operation of precipitation water infiltration systems
 
|-
 
|-
| ATV-DVWK-M 153 || Handlungsempfehlungen zum Umgang mit Regenwasser
+
| ATV-DVWK-M 153 || Recommendations for handling rainwater
 
|-
 
|-
| ATV-A 121 || örtliche Niederschlag / Starkregenauswertung nach Wiederkehrzeit und Dauer 
+
| ATV-A 121 || local precipitation / heavy rainfall analysis according to return period and duration
 
|-
 
|-
| DWA-A 117 || Bemessung von Regenrückhalteräumen
+
| DWA-A 117 || Design of rain retention spaces
 
|-
 
|-
| Kostra || Starkniederschlagshöhen für Deutschland
+
| Kostra || Heavy precipitation amounts for Germany
 
|-
 
|-
| DIN 4261-1,Kapitel 9 || Kleinkläranlagen, Verbringung von biologisch behandeltem Abwasser in den Untergrund
+
| DIN 4261-1, Kapitel 9 || Small wastewater treatment plants, transport underground of biologically treated wastewater
 
|-
 
|-
| EN 752 || Entwässerung außerhalb von Gebäuden...
+
| EN 752 || Drainage outside of buildings…
 
|-
 
|-
| ATV A 118 || Hydraulische Bemessung und Nachweis von Entwässerungssystemen
+
| ATV A 118 || Hydraulic design and verification of drainage systems
 
|-
 
|-
| ATV A 118 || Richtlinien für die Bemessung von Regenentlastungsanlagen in Mischwasserkanälen
+
| ATV A 118 || Guidelines for the design of rainwater discharge systems in mixed water sewers
 
|}
 
|}
  
==Anzeige- und Genehmigungspflichten==  
+
=Obligations to notify and obtain license=  
  
 
{| class="wikitable" style="text-align:rechts"
 
{| class="wikitable" style="text-align:rechts"
 
|-
 
|-
! Regelungsbereich !! Regelwerk !! Inhalt
+
! Scope !! Policy !! Content
 
|-
 
|-
| rowspan="1" | '''EU-Recht'''  
+
| rowspan="1" | '''EU legislation'''  
| EG-Richtlinie 76/464/EWG / 1976
+
| Anzeige- und Genehmigungspflichten
EG-Richtlinie 80/68/EWG / 1979 || Verschmutzung infolge der Ableitung bestimmter gefährlicher Stoffe in die Gewässer der Gemeinschaft Schutz des Grundwassers gegen Verschmutzung durch bestimmte gefährliche Stoffe
+
EG-Directive 80/68/EWG / 1979 || Pollution resulting from the discharge of specific dangerous substances into community waters. Protection of groundwater against pollution by specific dangerous substances
 
|-
 
|-
| rowspan="2" | '''Bundesrecht'''  
+
| rowspan="2" | '''Federal legislation'''  
| Wasserhaushaltsgesetz WHG || Versickerungsanlagen sind nach dem WHG erlaubnispflichtig, die Länder können seit 1996 die Erlaubnispflicht aufheben, Grundwasserverordnung
+
| Household water law WHG || In accordance with the WHG, infiltration plants require a licence, since 1996 the States have been able to abolish the licence requirement,  
 +
groundwater regulation
 +
 
 
|-
 
|-
| BauGB || Baugesetzbuch
+
| Building Code || Building Code
 
|-
 
|-
| rowspan="5" | '''Landesrecht'''  
+
| rowspan="5" | '''State legislation'''  
| Landesbauordnung || Angabe der Systemart und Größe im Bauantrag, die meisten Landesbauordnungen fördern oder verlangen die dezentrale Niederschlagswasserversickerung inzwischen
+
| State Building Regulation || Specification of the type of system and size in the building application, most state building regulations meanwhile promote or demand the decentralized infiltration of precipitation water
 
|-
 
|-
| AVBWasserV §3 || Antrag auf Teilbefreiung vom Anschluss- und Benutzungszwang an die öffentliche Abwasseranlage Anzeigepflicht vor Errichtung der Anlage beim kommunalen Wasserversorger
+
| Wastewater Regulation || Request for partial exemption from the obligation to connect and use the public sewage system. Obligation to declare prior to construction of the system at the municipal water utility
 
|-
 
|-
| Landeswassergesetz || evtl. Pflicht zur Versickerung von Niederschlagswasser
+
| State Water Law || possible obligation to infiltrate rainwater
 
|-
 
|-
| Landeswassergesetz || evtl. Erlaubnis der unteren Wasserbehörde bei Versickerung
+
| State Water Law || possible permission of the subsidiary water authority for infiltration
 
|-
 
|-
| kommunale Abwassersatzung || evtl. Antrag auf Teilbefreiung vom Anschluss- und Benutzungszwang beim kommunalen Wasserentsorger
+
| kommunale Abwassersatzung || possible application for partial exemption from connection and compulsory use at the municipal water disposal company
 
|}
 
|}
 
Test
 
  
 
=Weblinks=
 
=Weblinks=

Aktuelle Version vom 29. März 2019, 09:27 Uhr

Sprachen:
Deutsch • ‎English


Infiltration and retention

In water management, experience asserts that rainwater should be infiltrated at the place where it accumulates. If this is not possible, then in many cases the temporary storage (attenuation or retention) of rainwater is required in attenuation volumes in order to protect the drainage systems from overloading and to limit their dimension.

Advantages of rainwater infiltration

For end users:

  • stormwater fees are saved
  • the local microclimate is improved

For municipalities:

  • lower costs for flood protection / flood prevention
  • lower costs for sewer construction, sewer rehabilitation and sewage plant operation
  • lower connection costs for new developments
  • protection of the groundwater supply

Advantages of rainwater retention:

  • limiting area discharge, reducing flood risk
  • lower costs in sewer construction, sewer rehabilitation and sewage plant operation
  • connection of new developments to existing, full-capacity drainage systems
  • relief of overloaded sewer networks

Basic principles

Quality of rainwater runoff

The runoff from paved surfaces are classified into the categories of non-hazardous, tolerable and intolerable according to their material concentration and thereby possibly associated potential hazards to groundwater in targeted rainwater infiltration.

Non-hazardous rainwater runoff

Non-hazardous rainwater runoff can be infiltrated (e.g. in trenches) without pretreatment measures through the unsaturated zone (below the root zone and above the groundwater level).

Tolerable rainwater runoff

Tolerable rainwater runoff can be infiltrated through the unsaturated zone after suitable pretreatment or using cleaning processes (sedimentation system, rainwater cisterns, overgrown soil, etc.).

Intolerable rainwater runoff

Intolerable rainwater runoff can only be infiltrated after pretreatment.

Surface / Area Qualitative evaluation
Green roofs, fields and cultivated land; roof surfaces without the use of uncoated metals (copper, zinc and lead), terrace surfaces in residential and similar commercial areas non-hazardous
Roofs with usual proportions of uncoated metals, cycle tracks and footpaths in residential areas, calm traffic areas; lawns and car parking without frequent vehicle changes; as well as lightly used vehicle areas (up to DTV 300 vehicles); streets with DTV 300 - 5,000 vehicles, e.g. access roads, residential and district streets; airport tarmac; roofs in commercial and industrial areas with significant air pollution, see DWA-A138. tolerable
Lawns and streets in commercial and industrial areas with significant air pollution; for special zones see DWA intolerable

Source DWA-A138, DTV = average daily traffic intensity

Soil composition

Infiltration capacity of the soil

Overview of different kf-values for soils

The underground composition is of crucial importance for rainwater infiltration. The permeability coefficient (kf-value) is a measure of water permeability of the soil. The permeability coefficient should be between 10-3 and 10-6 in order to ensure the functionality of the infiltration system.

In order to avoid over-dimensioning of the system, the kf-value should be determined as accurately as possible through investigation. There are professional geotechnical experts for this purpose.

Quick test for soil composition

If the kf-value is unknown, then an approximation of the underground infiltration can be isolated based on the following short test.

Test pit
  1. Dig a 50 x 50 cm wide and approx. 30 cm deep pit. Important: Do not enter the pit to avoid compression!
  2. Cover the soil with a gravel layer to prevent soil flotation. Insert a measuring rod into the ground. 10 cm above the pit bottom place a mark on the measuring rod.
  3. Now fill the pit with water and replenish for 1-2 hours regularly (e.g. garden hose).
  4. Fill water up to the mark. After 10 minutes, fill as much water as necessary to raise the water level back to the mark using a measuring bucket. The soil permeability can be estimated from the quantity of refilled water.
  5. Repeat step 4 as many times (at least 3 times), until a consistent value is established.

Evaluation: Water quantity < 1.5 litres in 10 minutes: little infiltration possible (silt)
Water quantity = 1.5 litres in 10 minutes: infiltration possible (silty sand)
Water quantity > 3 litres in 10 minutes: good infiltration possible (sand, gravel)

Cleaning options for precipitation water

The contamination of underground and surface water from rainwater from roofs and traffic areas can be considered qualitatively and quantitatively by using simple assessment procedures (ATV DVWK-M153). Depending on the result, various measures for handling rainwater must be taken to ensure adequate water protection.

For discharge into a trench, minimum protection requires coarse filtration.

Important: with rainwater harvesting cisterns

According to DIN 1989-1, underground infiltrations systems (trenches) are equivalent to infiltration systems in active soil areas in terms of qualitative aspects, provided the inlet water comes from a rainwater harvesting system with non-metallic roof areas.

Sedimentation and filter chamber, sedimentation systems

Sedimentation and filter chamber

Systems with a settling chamber in which the flow conditions allow specific substances heavier than water sink and specific lighter substances float are referred to as sedimentation systems.

Collection and filter chambers consist of a sedimentation area in which heavy particles settle and a filter that prevents light coarse contaminants from entering the downstream storage. Even light materials are retained in the chamber with an immersion pipe. Depending on the amount of dirt, they must be cleaned regularly. The total water discharged from roof is filtered and supplied to the tank. In Germany the chambers are designed in accordance with ATV DVWK-M153, corresponding to the expected amount of dirt and connected roof area.

Soil passages

Soil passages

Contaminants from flowing rainwater are retained and stored or degraded by physical, chemical and if necessary, biological processes with passage through soil layers or in trough-trench systems or unsealed surfaces such as grass pavers. Thus passage through overgrown topsoil is more effective than through a non-vegetated soil zone. The protective cover layers over groundwater must not be penetrated.

Flushable and camera-accessible trenches

Should contaminants penetrate into the trench despite pre-cleaning, it is very important that subsequent cleaning is possible. In many trenches e.g. box systems, only the flushing ducts can be cleaned afterwards. However fine contaminates pass through the slots in the flushing ducts and gradually clog the floors and walls of these trenches. Ultimately these can only be dug out completely if they have lost their infiltration capacity. With DRAINMAX Tunnel trenches for example, the critical walls and floors can be inspected with a camera through adequate connection chambers and are completely flushable. Contaminants either are retained in the coarse filter of the sedimentation and filter chamber or settle in the sedimentation area. The coarse filter can be removed and emptied after the flushing process. The parallel rows of trenches are additionally protected by the long settling section in the seepage pipe and the additional settling possibility in the inspection and flushing chamber. This guarantees a constant infiltration performance long-term.

Construction of an infiltration system

  1. Distance to MHGW (mean highest groundwater level) from the bottom of the system: > 1 m
  2. Soil permeability > 1 x 10-6 (with lower values see retention)
  3. Soil permeability < 1 x 10-3 (with higher permeability too little treatment)

Trench infiltration with DRAINMAX Tunnel

Trench infiltration with DRAINMAX Tunnel

1. DRAINMAX Tunnel 5. Topsoil
2. Tunnel side and top backfill 6. Sedimentation/filter chamber
3. Geotextile 7. Rainwater inlet
4. Tunnel overburden

Trough-trench infiltration with DRAINMAX Tunnel

Trough-trench infiltration with DRAINMAX Tunnel

1. DRAINMAX Tunnel 6. Infiltration trough
2. Tunnel side and top backfil 7. Rainwater inlet
3. Geotextile 8. Distance to groundwater
4. Tunnel overburden 9. Active soil zone
5. Topsoil 10. Maximum water level


DRAINMAX Tunnel System for commercial properties

DRAINMAX Tunnel System for commercial properties

1. DRAINMAX Tunnel 7. Sedimentation/filter chamber
2. Tunnel side and top backfill 8. Flushing chamber
3. Geotextile 9. Rainwater inlet
4. Tunnel overburden 10. Maximum water level
5. Topsoil 11. Geotextile composite bottom layer
6. Rainwater distribution

Construction of a retention system

Retention volume

Retention cistern with throttle discharge
Retention cistern with throttle discharge and usable volume

There are several options for the retention of rainwater:

  • Storage with pure retention and throttle discharge
  • Storage with combined retention and use and throttle discharge


The combination of rainwater harvesting and rainwater retention in a cistern is particularly interesting for smaller systems for single-family homes since the costs for excavation and delivery are incurred only once and the cistern is not significantly more expensive.

  • Retention with approved partial infiltration and throttle discharge


With permitted partial infiltration, the DRAINMAX system with tunnel elements is an extremely interesting alternative. The low height offset between inlet and outlet in combination with large space flexibility and a very high storage volume are the advantages of this variant. If no water is allowed to enter the surrounding soil from the system, it can be sealed with an EPDM foil on site.

DRAINMAX Tunnel system

1. DRAINMAX Tunnel 6. Topsoil
2. Tunnel side and top backfill 7. Sedimentation/filter chamber
3. Geotextile 8. Throttle chamber
4. Enclosed sheet basin made from EPDM and geotextile 9. Discharge throttle
5. Tunnel overburden 10. Rainwater inlet

Throttle discharge

In a retention system the water is supplied into the drainage system with a throttled flow rate. The throttle discharge corresponds to the permitted outflow of the sealed area connected to the drainage system. Most of the time this discharge corresponds to the natural flow before sealing the area.

In the retention system the permissible throttle discharge is either supplied to a downstream drainage system by means of a lift pump or through a discharge throttle provided the height conditions allow. According to DWA-A 117, the arithmetic average of the values of the throttle curve is to be set for uncontrolled throttling (fixed throttle/vortex throttle).

Compared to the vortex or fixed throttle, continuous throttles make sure that the maximum permitted water quantity Q drains constantly, irrespective of the impounding depth H. As a result, the retention tank with continuous throttle can be dimensioned by 10% to 30% smaller than with fixed throttle discharge or vortex throttles.

Fixed throttle
Vortex throttle
Continuous throttle

Exp. throttle curve for maximum admissible water quantity of 31 L/s

Throttle diagram

1. Fixed throttle (arithmetic mean = 21 L/s)

2. Vortex throttle (arithmetic mean = 21 L/s)

3. Continuous discharge throttle (31 L/s)


Fixed throttle

The simplest form of a fixed or static throttle is a simple flow restrictor. The discharge value Q of the fixed throttle depends on the hydrostatic pressure resulting from the impounding depth H.

Vortex throttle

A spiral stream of variable strength with a central rotating air core is formed by the tangential feed in the vortex throttle depending on the water level. However this does not lead to a continuous throttle outflow. The vortex throttle has the advantage of requiring less space and lower risk of blockages due to the larger remaining cross-section compared to the other throttle types. These advantages are rarely relevant with decentralized rainwater retention.

Continuous throttle

The outlet flow is constant with the continuous discharge throttle irrespective of the impounding depth H. The float adjusts the restrictor opening at the impounding depth by means of a lever arm. Coarse pre-cleaning of rainwater is necessary for the trouble-free operation of the throttle.


Calculation example of required storage volume

The crucial rain yield rD(n), the duration D and frequency n [L/s-ha] must be determined iteratively (see Dimensioning of infiltration or retention systems).

Verf = ((Ared x rD(n) x 10-4) – Qdr ) x D x 60 x 10-3
Verf = required storage volume in m³
Ared = connected paved surfaces in m² (5,000 m² in example)
rD(n) = crucial rainfall in L/sha (e.g. KOSTRA-Data Aachen, see Dimensioning of infiltration or retention systems)
Qdr = discharge throttle value in L/s (the arithmetic mean of the throttle curve with non-continuous throttles, see diagram of throttle curves, 21 L/s in the example)
D = Duration in min (in example, 30 min with the fixed throttle and vortex throttle, 20 min with the continuous throttle)
fixed throttle = vortex throttle: Verf = ((5,000 x 104.8 x 10-4) – 21) x 30 x 60 x 10-3 = 56.6 m³
continuous throttle: Verf = ((5,000 x 131.7 x 10-4) – 31) x 20 x 60 x 10-3 = 41.8 m³ (- 26 %)

The larger the permitted throttle outflow in relation to the connected areas, the greater the difference. This difference leads to correspondingly lower total costs for the retention system.

Dimensioning of infiltration or retention systems

Also see Online Planner

Rainwater runoff

The calculation of rainwater runoff is based on the knowledge that heavy rains last short durations and low rains persist for longer. The rainfall yield declines at the same statistical frequency with increasing rainfall duration. The relationship between rainfall yield, duration and frequency is determined by the statistical analysis of precipitation registrations. Simple calculation methods in Germany are used in accord with DWA-A 117. For this a statistical rainfall with selected duration D and frequency n should be used as load case for calculation. For the determination of rain yield refer to the "amount of heavy peak rainfall in Germany - KOSTRA" (see table for a sample location).

Rain duration D r D(1) l/(sha) r D(0,2) l/(sha)
5 min 135.0 243.0
10 min 113.0 183.9
15 min 97.2 152.6
20 min 85.3 131.7
30 min 69.5 104.8
45 min 52.9 81.2
60 min 43.1 66.8
90 min 32.3 49.7
2 h 26.4 40.3
3 h 19.8 29.9
4 h 16.1 24.3
6 h 12.1 18.0
9 h 9.1 13.4
12 h 7.4 10.9
18 h 5.4 7.9
24 h 4.3 6.5
48 h 2.6 3.7
72 h 2.1 2.9

KOSTRA data sample location

Inflow to infiltration or retention systems

Qzu = 10-7 x rD(n) x Ared (1.)
Qzu = Inflow to infiltration system in m³/s
rD(n) = Rain yield for duration D and frequency n [L/sha]
Ared = connected paved areas in m²

Discharge from the infiltration system

Darcy’s Law is used to calculate the discharge from an infiltration system:

Qs = (b+0,5h) x L x ½ x kf (2.a)
kf = Permeability coefficient of the saturated soil in m/s
b = Bottom width of the trench in m
h = Height of the trench in m
L = Length of the trench in m

Discharge from the retention system

Continuity condition

Verf = L x b x h x sRR = (∑Qzu - ∑Qs) x D x 60 (3.)
Verf = required storage volume in m³
D = Rain duration in min

Infiltration: If only formulas 1. and 2.a are used for formula 3 to calculate L, then this will result in a significant trench length and volume.

SRR = Storage coefficient of the trench

Retention: Here, only formulas 1. and 2.b are used in formula 3. Ver = (∑Qzu - ∑Qs) x D x 60 The significant rain yield rD(n) of duration D and frequency n [L/s-ha] must be iteratively determined.

Ver = (∑Qzu - ∑Qs) x D x 60

The crucial rain yield rD(n), the duration D and frequency n [L/sha] must be determined iteratively.

Overflow frequency

For statistical determination of rainwater outflows, the assumed frequency of rain from the rain yield curve is crucial. This value depends on the economic importance of the area and is related to the frequency with which the proposed system is congested.

Frequency of dimensioning system (once in n years) Location
1 in 1 Rural area
1 in 2 Residential area
1 in 2 City centers, industrial and commercial areas with flood assessment
1 in 5 City centers, industrial and commercial areas without flood assessment
1 in 10 Underground traffic infrastructure, subways

Source: ATV A118

Flood verification DIN 1986-100:2016-09 (Germany)

Drainage systems for the discharge of precipitation water from small properties, so long as the sewer network provider has given no other guideline, without a more effective run-off surface, are sufficient for DN 150 connection to the sewer. The rule applies in the same sense to infiltration systems designed according to DWA-A 138 with T = 5 a and a dimensioning rainfall according to KOSTRA-DWD-2010. It is assumed that due to terrain condition and architectural building plans no backed-up water from the system will penetrate into the connected or neighbouring buildings and exceed any other official regulations.

Ground conduits from properties, according to DIN EN 752 from 200 ha Ages i.e. from approximately 60 ha AE,b, that drain larger, harmless flood-prone yard, park or other outdoor systems can be designed according to DWA-A 118:2006, Table 4. Here the yearly occurance of the dimensioning rainfall cannot be less once within two years.

Shortest normative rain period in relation to terrain slope and degree of sealing:

average terrain slope Sealing shortest rain period

(according to this norm r2 in min)

< 1% ≤ 50% 15 min
> 50% 10 min
1% bis 4% - 10 min
> 4% ≤ 50% 10 min
> 50% 5 min

Source: DWA-A-118:2006, Table 4

For the difference in the amount of rainwater accumulated on a sealed surface of a property, VRück in m³ (see Equation 20), between the minimum 30-year rain event and the 2-year dimensioning rain, proof of harmless flooding on the property must be provided. If an exceptional level of safety is required, the yearly occurance of the dimensioning rain is chosen as greater than 30 a. The harmless flooding can take place on the property, e.g. with curbs or troughs, or through other retention areas, like retention basins, if people, animals or material goods are not endangered, so long as the precipitation water is not discharged on other fields. The following flood verification for guidance is dependent on the local conditions and if necessary for parts of the drainage system (e.g. in the calming areas).

Equation 20

Vrück = (r(D,30) x Ages – ( r(D,2) x CDach + r(D,2) x AFaG x CFaG)) x D x 60 / (10,000 x 1000)

VRück the to-be retained rainwater amount, m³

r(D,2) rain event with period D and 30-year return time

D the shortest normative rain period, min, for the dimensioning of drainage outside of a building according to DWA-A-118, Table 4, usually D = 5 min

C the run-off coefficient

ADach the total building roof area, m²

AFaG the total sealed surface outside of the building, m²

Ages the total sealed surface oft he property, m², hence Ages = ADach + AFaG

If the ground conduits are dimensioned according to DWA-A-118:2006, Table 4, then the dimensioning discharge, usually larger, instead can be set according to Equation (21) for the maximum discharge of the ground conduits at full charge Qvoll:

Equation 21

Vrück = ((r(D,30)) x Ages/ 1000)– Qvoll x D x 60/1000

VRück the to-be retained rainwater amount, m³

D D = 5, 10 and 15 minutes. The larger of these three values is normative for VRück*

Qvoll max. discharge of the ground conduits at full charge, L/s

Ages the total sealed surface of the property, m², hence Ages = ADach + AFaG

Should the rain catchment surfaces of the property be mostly roof areas and not harmless, flood-prone surfaces (e.g. > 70 %, here as well inner courtyards), the flood verification is demonstrated in connection with emergency drainage of a 5-min, 100-year rain event (r(5,100)).

In the case of limited loading, in addition to the flood verification, the calculation of the required retention volume (Rain Retention Area (RRA)) must be carried out with the „simplest procedure“ in accordance with DWA-A 117. For simplicity’s sake, it is assumed that the yearly occurance T of the dimensioning rain (uniform in relation to the total effective property area) corresponds to the permissible exceedance frequency of the RRA. The loading restriction must include the throttle discharge, L/s and the yearly occurance T of the permitted excess. For the calculation of volume related dimensioning exercises, such as the dimensioning of precipitation water retention areas, the mean discharge coefficients Cm according to Table 9 are to be used to determine the effective area. The dimensioning of rain retention areas must considered according to DWA-A 117:2013 for the run-off entering the drainage system in relation to both the sealed area AE,b as well as from the non-sealed area (Table 9, No. 3) from inlet to outlet in the drainage system. The determined surface types will be simply called AFaG in this norm, with the mean run-off coefficients Cm multiplied and linked to the calculated value Au. The required storage volume VRRR will be determined according to the maximum difference between the rainfall amount and the discharge volume through the throttle in a specific time period.

In accordance with DWA-A 117, Equation (22) applies for property drainage systems for the design of retention areas (RRA).

Equation 22

VRRA = Au x rD,T / 10,000 x D x Fz x 0.06 – D x fz x QDr x 0.06

Equation 22 cooresponds to the calculation of the required retention volume related to the inlet restriction according to DWA-A 117 using the „simple method“ (see Capital 3.2 Throttle discharge for formula).

Example calculation to-be retained rainwater amount according to flood verification

Location: Aachen Connected catchment surfaces: Building surfaces: ADach = 1,250 m², pitched tiled roof CDach = 0.8 Catchment surfaces outside of the building: AFaG = 4,445 m², asphalt, CFaG = 0.9 Total sealed surface of the property: Ages = 5,695 m² (Ared = 5,000 m²) Medium terrain slope: < 1% sealing: > 50 %

Calculation according to Equation 20

Vrück = (r(D,30) x Ages – (r(D,2) x CDach + r(D,2) x AFaG x CFaG)) x D x 60 / (10000 x 1000)

with: D = 10 Min (from DWA-A-118:2006, Table 4)

r(D,30) = 273 L/sha r(D,2) = 148 L/sha Vrück = 273 x 5,695 – (148 x 1,250 x 0.8 + 148 x 4,445 x 0.9) x 10 x 60 / (10,000 x 1000) = 48.9 m³

Calculation according to Equation 21

Vrück = ((r(D,30) x Ages / 10,000) – Qvoll) x D x 60 /1000

With: single verification of the dimensioning rainfall quantity:

a) r(5.30) = 377 L/sha (from DIN 1986-100, Table A.1 Rain Quantity in Germany)

b) r(10.30) = 273 L/sha

c) r(15.30) = 223 L/sha Qvoll = 100.0 L/s

a) Vrück = ((377 x 5,695 / 10,000) – 100.0) x 5 x 60 / 1000 = 34.4 m³

b) Vrück = ((273 x 5,695 / 10,000) – 100.0 ) x 10 x 60 / 1000 = 33.3 m³

c) Vrück = ((223 x 5,695 / 10,000) – 100.0 ) x 15 x 60 / 1000 = 24.3 m³

The larger of the three values Vrück is normative.

Calculation according to Equation 22

The impounding volume from the standard calculation (according to the inlet limitation) results from Cap. 3.2.4 as 41.8 m³.

Conclusion:

This resulting larger volume is relevant for the calculations for flood verification and the inlet limitation. The relevant size of the retention space is calculated from Equation 18 as 48.9 m³. With this based on the flood verification, the required retention volume is increased by 7.1 m³ (17%). At the latest when the flood volume cannot be represented on the surface then the underground storage volumes must be constructed larger.

Sample calculations for infiltration with DRAINMAX Tunnel

a) with value D = 15min and n = 0.2 = Example for various international regions

Location: Aachen
Ared= 100 m²
Measured rainfall: r15,n=0.2 = 152.6 L/(sha)
kf = 1*10-4 m/s (medium sand)
srr = 0.56 (DRAINMAX Tunnel installation according to German Institute for Civil Engineering)
fz = 1.1

Sample calculation for INTEWA DRAINMAX Tunnel in gravel bed:

B = 1.85 m, H = 1 m, L = 2.25 m
Lerf,rigole = 1.31 m
Verf,rigole = 1.36 m³ (= B x H x Lerf,rigole x srr = 1.85 m x 1 m x 1.31 m x 0.56)
Required number of DRAINMAX Tunnels: LLerf,rigole / L = 0.82

b) With iteration = Example for Germany

Location: Aachen
Ared = 100 m²
Measured rainfall: r15, n=0.2 = 152.6 l/(s*ha)
kf = 1*10-4 m/s (medium sand)
Duration D [min] Rain yeld r [L/sha] Lerf,rigole [m] Verf,rigole [m³]
5 243.00 0.75 0.77
10 183.90 1.09 1.13
15 152.60 1.31 1.36
20 131.70 1.46 1.51
30 104.80 1.64 1.69
45 81.20 1.74 1.80
60 66.80 1.76 1.83
90 49.70 1.70 1.76
120 40.30 1.62 1.68
180 29.90 1.46 1.51
240 24.30 1.33 1.38
360 18.00 1.12 1.16
540 13.40 0.91 0.95
720 10.90 0.78 0.81
1080 7.90 0.60 0.62
1440 6.50 0.51 0.52
2880 3.70 0.3 0.31
4320 2.90 0.24 0.25

c. Table for rough estimation of small systems with r15,n=0.2

kf (m/s) e.g. location Aachen (D) r15,0.2=152.6 L/sha e.g. location Berlin (D) r15,0.2=213.1 L/sha
A=100 m2 A=150 m2 A=200 m2 A=100 m2 A=150 m2 A=200 m2
1*10-4 Volume in m3 1.36 2.04 2.72 1.90 2.85 3.79
1*10-5 Volume in m3 1.49 2.24 2.99 2.09 3.13 4.79
1*10-6 Volume in m3 1.51 2.26 3.02 2.11 3.16 4.21

Rough estimation of retention volume

The following method of calculation can be used for a rough estimation of required retention volume with specified rain duration.

Example calculation:

Permitted discharge from property: 1.5 L/sha
Property size: 0.105 ha
Rain yield r15(1) = 108 L/sha
Rain yield r15(2) = 193 L/sha
Surface x Runoff coefficient x Rain yield = Qr15(2)
231 m2 x 1 x 0.0193 L/s x m2 = 4.46 L/s
114 m2 x 0.8 x 0.0193 L/s x m2 = 1.76 L/s
Total rainwater runoff Qrges = 6.22 L/s
Approved discharge quantity: Qab = 0.105 ha (property size) x 1.5 L/sha
= 0.158 L/s
Rainwater quantity for retention: Qs = Qr15(0.2)ges - Qab
= 6.22 L/s – 0.158 L/s = 6.06 L/s
Required backwater volume Verf: (The retention system must absorb Qs for 15 min.).
Verf = Qs x 60 x 15 = Qs x 900
= 6.06 L/s x 900 s = 5.5 m3

Accurate dimensioning of a trench or retention system with planning software

Since calculation of the required trench volume is iterative, planning software such as the RAINPLANER is better designed for solving it.

Dimensioning surface infiltration

As = Ared / (kr x sf x 107 / 2 x r D(n) –1)
Ared = connected paved surfaces
sf = Joints proportion in a permeable paved area (0 < sf =< 1)
kr = Permeability coefficient in the considered infiltration layer
rD(n) = Rain yield
Example:
Ared = 300 m2
sf = 1 (INTEWA grass grid pavers)
kr = 2 x 10-4 m/s
r D(n) = from KOSTRA table with n=0.2/a and D=10 min: r10(0.2) = 204.60 L/sha
As = 300 / ( 2 x 10-4 x 1 x 107 / 2 x 204.6 –1) = 77 m2

Dimensioning infiltration trenches behind small wastewater treatment systems

According to DIN 4261-1, version 2002, the water discharged from SWWTPs can be infiltrated through trenches in soils with kf = 5 x 10-7 to 5 x 10-3 m/s. As the base of infiltration system can clog up with time, only the side areas remain effective in the long run. A large retention volume is an advantage for variable infiltration efficiency i.e. during frost or uneven loading of the trench. The following simplified dimensioning methods shall apply according to DIN:


Trenches behind small wastewater treatment systems
Required wall area (m2/inhabitant value PE):
1 m2 / PE to 1.5 m2 / PE with: Sand-gravel mixture, sand, light silty sand
2 m2 / PE to 2.5 m2 / PE with: Silt (also light clay), sand-silt mixture, stone-loam mixture
Required number for example of DRAINMAX Tunnel:
Base element 2.25 m length x 0.8 m heigth x 2 sides
As = 3.6 m2 per tunnel without front walls
PE to 1.5 m²/PE to 2.5 m²/PE
4 1 pcs. 2 pcs.
8 1 pcs. 4 pcs.
12 3 pcs. 6 pcs.
16 4 pcs. 8 pcs.

A specified calculation must be done with other soil conditions and higher PE values.


Comparison between DRAINMAX Tunnel and pipe trench variants

According to EN 12566-3 for small wastewater treatment plants (SWWTPs) 150 L / day / inhabitant (PE) has the following daily distribution:

3h = 30%
3h = 15%
6h = 0%
2h = 40%
3h = 15%
7h = 0%

When using a classic pipe trench, the largest flow rate must be determined. This occurs within 2h with 40%. For a SWWTP with 5 PE this is calculated as follows:

40 % in 2 h from 750 L/day
=> 300 L/2h
=> 0.0417 L/s

When using the DRAINMAX Tunnel, the daily volume can be stored in the trench. The largest flow rate is then calculated as follows:

100 % in 24 h from 750 L/day
=> 750 L/24 h
=> 0.0087 L/s

=> this flow rate is 4.8 times smaller than with the pipe trench variant
=> the DRAINMAX tunnel can be dimensioned approx. 4.8 times smaller than the pipe trench

Legal framework conditions in Germany

When planning and installing an infiltration or retention system, the current versions of the following regulations must be observed:

Scope Policy Content
Water supply Arbeitsblatt DWA-A 138 Planning, construction and operation of precipitation water infiltration systems
ATV-DVWK-M 153 Recommendations for handling rainwater
ATV-A 121 local precipitation / heavy rainfall analysis according to return period and duration
DWA-A 117 Design of rain retention spaces
Kostra Heavy precipitation amounts for Germany
DIN 4261-1, Kapitel 9 Small wastewater treatment plants, transport underground of biologically treated wastewater
EN 752 Drainage outside of buildings…
ATV A 118 Hydraulic design and verification of drainage systems
ATV A 118 Guidelines for the design of rainwater discharge systems in mixed water sewers

Obligations to notify and obtain license

Scope Policy Content
EU legislation Anzeige- und Genehmigungspflichten

EG-Directive 80/68/EWG / 1979 || Pollution resulting from the discharge of specific dangerous substances into community waters. Protection of groundwater against pollution by specific dangerous substances

Federal legislation Household water law WHG In accordance with the WHG, infiltration plants require a licence, since 1996 the States have been able to abolish the licence requirement,

groundwater regulation

Building Code Building Code
State legislation State Building Regulation Specification of the type of system and size in the building application, most state building regulations meanwhile promote or demand the decentralized infiltration of precipitation water
Wastewater Regulation Request for partial exemption from the obligation to connect and use the public sewage system. Obligation to declare prior to construction of the system at the municipal water utility
State Water Law possible obligation to infiltrate rainwater
State Water Law possible permission of the subsidiary water authority for infiltration
kommunale Abwassersatzung possible application for partial exemption from connection and compulsory use at the municipal water disposal company

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