Changes

Jump to navigation Jump to search
1,225 bytes added ,  4 years ago
m
no edit summary
Line 9: Line 9:     
===Height===
 
===Height===
Freeboards should be adequate to prevent over-topping during storm events and allow overflow of less frequent storm events through controlled and protected emergency overflow points. Berm freeboards should also consider berm soil consolidation and subsidence, and also that the wetland can gradually fill with vegetation and with sediments which increase flow resistance and decrease freeboard during wetland life.
+
* Freeboards should be adequate to prevent over-topping during storm events and allow overflow of less frequent storm events through controlled and protected emergency overflow points. Berm freeboards should also consider berm soil consolidation and subsidence, and also that the wetland can gradually fill with vegetation and with sediments which increase flow resistance and decrease freeboard during wetland life.
 +
* Controlled overflow points that are riprapped dips in the surface or concrete weirs should be incorporated into the top of the berm of each wetland cell so that if the wetland is overtopped the flow exiting the wetland does not cut channels into the top of the berm that could compromise the integrity of the berm.
    
===Top width===
 
===Top width===
Line 16: Line 17:  
*Berms ≥ 5m in width are less likely to be fully penetrated by muskrats or nutrias. Furthermore, water containment berms are subject to local dam safety regulations
 
*Berms ≥ 5m in width are less likely to be fully penetrated by muskrats or nutrias. Furthermore, water containment berms are subject to local dam safety regulations
   −
==Resources==
+
===Slope===
 +
Berm slope is dictated by geotechnical considerations and slope-stability analysis.
 +
*Maximum berm slopes typically used are 2:1 (horizontal: vertical).
 +
* However, it is better to keep slopes at 3.5:1 or lower angle to minimize sloughing of the slopes into the wetlands while maximizing wetted area in the wetlands.
 +
* A side slope of 5:1 or greater provides easier egress in case someone falls into the pond or wetland contained within.
 +
* Slopes up to 10:1 or 20:1 are used when a shallow littoral shelf is desired to create vegetation and habitat diversity. The side slopes may be rip-rapped with stone to reduce the potential for erosion or rodent burrowing.
 +
<ref>CH2MHill. (2014). Wetland Design Guidelines City of Saskatoon. Retrieved from https://www.saskatoon.ca/sites/default/files/documents/transportation-utilities/construction-design/new-neighbourhood-design/wetlands_design_guidelines.pdf</ref>

Navigation menu