The Importance of Stormwater Management
The importance of stormwater management is a widely discussed topic within the stormwater and property management industries. Stormwater management is often the broad term associated with inspection and maintenance of drainage infrastructure. The question is often raised: how to improve stormwater management to increase its effectiveness and mitigate flood risks? The answer to that is usually by taking action and doing inspections and maintenance of the stormwater system.
The trigger for us to perform maintenance is typically one of two reasons, either we have to, because something is not working correctly and it is causing water related problems, or more likely, because the owner is required to by a regulatory authority. Whether the reason is rehabilitation or regulatory, maintenance needs to be performed in order to satisfy either need.
Maintenance can be a wide range of items including sediment removal, improving infiltration, removal of pollutants, removal of oils and other liquids that collect in chambers, or the replacement of filters. The types of stormwater management systems dictate the scope of the maintenance.
Maintenance within detention basins often includes vegetation cutting and removal, erosion control, dewatering, stabilization, and re-grading. The methods for detention basin maintenance can be hand labor, heavy equipment work, hydro excavation or sometimes combinations of all three. Structural repairs to berms, outfalls, or outlet control structures (OCS) can also be done depending on their condition. Animal burrows in water retaining berms is an example of preventative structural maintenance item that will need to be done from time to time.
Outlet control structure maintenance includes clearing of trash racks, orifice openings, weirs, plates and grates on the various types of OCS units. The OCS is the single most important structure to be inspected or repaired in a maintenance cycle. The OCS dictates the detention time, outflow, and infiltration ability of the basin. If it is not working correctly, the entire basin is not functioning as it was engineered.
Green Infrastructure – The importance of stormwater management maintenance to Green Infrastructure (GI) measures are even more significant. Since Green Infrastructure stormwater management is done on a much smaller scale, the number of GI units is significantly greater than traditional stormwater best management practices (BMPs). GI units rely heavily on some type of infiltration component in order to achieve water quality and recharge. In terms of drainage and stormwater management, Green Infrastructure requires more frequent but less intensive maintenance.
Manufactured Treatment Devices, also referred to as MTD’s, includes all types of stormwater filtration systems, separators, and hydrodynamic separators. A stormwater management system or design can incorporate the use of an MTD coupled with a traditional detention basin or Green Infrastructure BMP. The importance of stormwater management maintenance is the most significant when it comes to MTD’s because of their highly engineered designs and performance standards.
No matter the Best Management Practice, often called the BMP, the driving factor for maintenance should be the existing conditions observed through routine inspections. Routine maintenance such as grass and vegetation cutting can be planned on a monthly basis, but more extensive and costly types of maintenance should be performed when warranted.
It is often prudent to budget for unexpected maintenance that might come up throughout the year, but if systems are properly maintained, it is often not necessary to do the maintenance until such issues are observed. A properly maintained BMP is a perfect example of the importance of stormwater management.
Contact one of our stormwater professionals at [email protected] to begin your discussion about stormwater management.