What Will My Stormwater Project Cost?
Stormwater is any rain or snow water that drains from a site. Such drainage into stream channels is called runoff. Runoff affects everyone, and all pay! Some costs may be in purchases or repairs, others in management.
Specific practices and structures that have proven effective in certain conditions are called best management practices or BMPs. We can incorporate several best practices on a small scale at home to reduce the amount of runoff, or improve the quality of stormwater passing through sites we influence.
What are costs of some best practices we can do at home?
Here, we will address
- Disconnecting a downspout from the municipal sewer system.
- Using a rain barrel
- Planting trees and landscape plants
- Riparian buffers
- Rain gardens
- and permeable paving systems
Disconnecting roof downspouts from municipal underground systems may allow us to soak the drainage up on site, given sufficient space. Under best conditions, we can disconnect a downspout from the receiving pipe and place a guide shoe to discharge 10 feet or farther from buildings into a permeable area. The outlet site must be able to soak up an inch of rainfall per hour, and standing water needs to drain from the site within 72 hours to meet acceptable standards in Pennsylvania. Costs may be about $50 or less per downspout. Much expense depends on needing to pipe under walkways or other hardscapes.
Rain barrels are small vessels that may be placed at roof downspouts. Installing a rain barrel may cost from $20 to $200, depending on connections and components. Kits can be inexpensive, but be sure to consider necessary lids, downspout interconnect bypasses, and barrels safe for the intended use. Any used barrels must be thoroughly cleaned to assure safety. Maintenance includes draining and disengaging the system for winter.
Planting landscape trees, shrubs and herbaceous plants brings many benefits that now have dollar values recognized. We may plant combinations according to their size, their site preference and purpose. One purpose is planting a riparian buffer alongside running water to protect the channel and bank zones. Small plants may cost a few cents, or may be transplanted from within the site. Potted plants could be purchased for $5 to $50. Tree seedlings may cost $3 to $5 or more. Trees with stem diameters from 1 ½ to 2 inches (measured 6 inches above the root flare) may cost about $75 to $170 depending on type and species. Bare rooted trees are usually less expensive than those packaged in containers or balled in burlap. Value and time spent planting trees often equals the purchase cost. This may include site preparation and installing protection such as tree stakes and planting tubes. Maintenance includes mulching, watering until they are fully established, pruning to manage structure, managing pests, and removing hardware as it becomes unneeded. Hiring maintenance crews could cost $120 to $150 per hour.
Properly designed rain gardens are shallow, landscaped depressions that allow runoff to infiltrate.
Construction costs may range from $7 to $11 per cubic foot. Garden drainage often depends on installing a course aggregate stone to a depth of perhaps 2 to 4 feet. It may need overflow drainage to be designed into the bed to ensure against flooding someone else’s property. Consult your Conservation District or design engineer to prepare correctly.
Permeable hardscapes can help reduce peak discharge and total runoff. Like all best practices, they must be designed to serve their load-bearing purposes. An aggregate stone bed provides the water drainage and storage allowing the surface to remain stable. Hardscapes designed to carry light vehicles may be installed for $15.50 to $20 per square foot. Areas meant only for foot traffic can be less expensive. Maintenance includes vacuuming to maintain porosity.
In summary, we defined stormwater as any water from precipitation. Surface water drainage is called runoff. Best practices are intended for specific purposes and may not be successful if improperly used.
This sheet discussed costs of some best practices we might install at home or hire done professionally.
Consult your municipal authorities and design expert to ensure legality and the best success.
If you have additional questions about stormwater, or you are just interested in learning more, you can find a full series of videos and articles in the Penn State Extension Stormwater Basics series.
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