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===Design considerations for ponds used for harvest and use===</noinclude> | ===Design considerations for ponds used for harvest and use===</noinclude> | ||
The first question to ask before selecting a constructed stormwater pond as the BMP is whether a pond is the most appropriate BMP. If the goal is to meet a volume retention requirement and the retention requirement can be met through infiltration of stormwater, then [https://stormwater.pca.state.mn.us/index.php?title=Stormwater_infiltration_Best_Management_Practices stormwater infiltration practices] should be considered. On soils conducive to infiltration and where site constraints do not exist, infiltration will typically be the most appropriate BMP. However, if site goals include other factors, such as replacing a water supply or irrigation of vegetation, harvest and use is an appropriate BMP. | The first question to ask before selecting a constructed stormwater pond as the BMP is whether a pond is the most appropriate BMP. If the goal is to meet a volume retention requirement and the retention requirement can be met through infiltration of stormwater, then [https://stormwater.pca.state.mn.us/index.php?title=Stormwater_infiltration_Best_Management_Practices stormwater infiltration practices] should be considered. On soils conducive to infiltration and where site constraints do not exist, infiltration will typically be the most appropriate BMP. However, if site goals include other factors, such as replacing a water supply or irrigation of vegetation, harvest and use is an appropriate BMP. | ||
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+ | [[File:Example reuse pond design.png|300px|thumb|alt=schematic of pond design|<font size=3>Example pond design for a harvest and use/reuse system.</font size>]] | ||
Ponds should be designed following guidance in [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_stormwater_ponds pond design guidance section] of this manual. However, there are or may be specific design considerations for stormwater ponds used in harvest and use/reuse systems. These design considerations are summarized below. | Ponds should be designed following guidance in [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_stormwater_ponds pond design guidance section] of this manual. However, there are or may be specific design considerations for stormwater ponds used in harvest and use/reuse systems. These design considerations are summarized below. |
Stormwater ponds can be used as the storage component of a stormwater harvest and use system. These ponds are multi-purpose, providing stormwater retention, sedimentation, and storage for later use. In this way, stormwater harvest and use systems can be part of a treatment train approach for stormwater management. Existing ponds can be retrofitted to serve as a water source for a harvest and use system.
If the pond is designed to meet the Construction Stormwater General Permit, several requirements must be met. Those are summarized here.
The first question to ask before selecting a constructed stormwater pond as the BMP is whether a pond is the most appropriate BMP. If the goal is to meet a volume retention requirement and the retention requirement can be met through infiltration of stormwater, then stormwater infiltration practices should be considered. On soils conducive to infiltration and where site constraints do not exist, infiltration will typically be the most appropriate BMP. However, if site goals include other factors, such as replacing a water supply or irrigation of vegetation, harvest and use is an appropriate BMP.
Ponds should be designed following guidance in pond design guidance section of this manual. However, there are or may be specific design considerations for stormwater ponds used in harvest and use/reuse systems. These design considerations are summarized below.
Below is a list of additional considerations that are not specifically addressed above.
Maximum Detention Time - Average Daily Temperature
Link to this table
Maximum Detention Time (days) to limit algae blooms: | Average Daily Temperature (F) |
---|---|
50 | 59 |
30 | 68 |
20 | 77 |