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mLine 81:
Line 81: − #Minimum depth: 1 m;+ − #Sized to ensure non-erosive velocities leaving forebay; + − #Maximum area: 20 % of total permanent pool+ − #Overall: minimum 3:1; + − #Forebay: minimum 2:1+ Line 102:
Line 102: − #5:1 For 3 m above and below permanent pool; + − #Maximum 3:1 elsewhere+ − #Minimum 450 mm; + − #Preferred pipe slope: >1%; + − #If submerged, obvert 150 mm below expected maximum ice depth+ − #Minimum: 450mm outlet pipe; + − #Preferred pipe slope: >1%; + − #If orifice control used, 75mm diameter minimum; + − #Minimum 100mm orifice preferable + − #Provided to approval of Municipality; + − #Provision of maintenance drawdown pipe preferred+
→Design
|Pre-treatment
|Pre-treatment
|style="text-align: left|
|style="text-align: left|
*Minimum depth: 1 m;
*Sized to ensure non-erosive velocities leaving forebay;
*Maximum area: 20 % of total permanent pool
|-
|-
|Length-to-Width Ratio
|Length-to-Width Ratio
|Maximize flow path and minimize short-circuiting potential
|Maximize flow path and minimize short-circuiting potential
|style="text-align: left|
|style="text-align: left|
*Overall: minimum 3:1;
*Forebay: minimum 2:1
|-
|-
|Permanent pool depth
|Permanent pool depth
|Safety
|Safety
|style="text-align: left|
|style="text-align: left|
*5:1 For 3 m above and below permanent pool;
*Maximum 3:1 elsewhere
|-
|-
|Inlet
|Inlet
|Avoid clogging/freezing
|Avoid clogging/freezing
|style="text-align: left|
|style="text-align: left|
*Minimum 450 mm;
*Preferred pipe slope: > 1 %;
*If submerged, obvert 150 mm below expected maximum ice depth
|-
|-
|Outlet (See also [[flow control]])
|Outlet (See also [[flow control]])
|Avoid clogging/freezing
|Avoid clogging/freezing
|style="text-align: left|
|style="text-align: left|
*Minimum: 450 mm outlet pipe;
*Preferred pipe slope: > 1 %;
*If orifice control used, 75 mm diameter minimum;
8Minimum 100 mm orifice preferable
|-
|-
|Maintenance access
|Maintenance access
|Access for backhoes or dredging equipment
|Access for backhoes or dredging equipment
|style="text-align: left|
|style="text-align: left|
*Provided to approval of Municipality;
*Provision of maintenance drawdown pipe preferred
|-
|-
|Buffer
|Buffer