IV. Integrated Stormwater Management Case Studies
IV. Integrated Stormwater Management Case Studies
As explained in the beginning of this Stewardship Toolkit, the ideal situation would be to combine several stormwater management practices for an integrated approach. An integrated approach is the most effective way to returning a disturbed hydrologic system to a near‐natural state. In some cases, combinations will become obvious as one particular enhancement increases the efficiency of another. For example, leading a rain barrel overflow hose to a rain garden, or using soil amendment practices adjacent to an infiltration trench to provide pretreatment. This section provides examples of integrated stormwater management designs for single‐family homes.
- Retrofitted Property, Santa Cruz, California
Santa Cruz County resident Ole Christensen has recently retrofitted his property in an effort to reduce his human impact on the diminishing freshwater sources of the region, by installing a 3,000 gallon underground cistern and by redesigning his landscape. He has installed a manually‐operated pump attached to the cistern for easy irrigation use. He has also replaced the preexisting turf grass with drought‐ and pest‐resistant plants, and has installed a decorative detention pond in the front yard on his property.
- Integrated Approach:
- Installed a 3,000 gallon subsurface water‐harvesting cistern with an accessible electric manual pump to reduce the amount of runoff leaving his property, and to store rainwater for irrigation
- Removal of turf grass and ornamental bushes
- Replacement of poorly‐drained sub‐soil with fine fill for better infiltration
- Construction of a berm to keep onsite‐runoff from leaving the property
- Re‐landscaped the property with drought‐tolerant and pest‐resistant plant species to reduce the need for fertilizers and pesticides
- Installed a permanent vernal pool filled with cobble stones to detain on‐site runoff
- Installed mulch for water conservation and filtering benefits
- Love’s Garden Project, Santa Cruz, California
A rain garden and dry creek bed retrofit transformed the drainage system of this property to one that replicates a pre‐developed hydrologic cycle.
- The dry creek bed (above left) acts to deliver stormwater away from the base of the house and solved a flooding problem in the front yard area
- It also disconnected the traditional stormwater management system of conveyance to the street
- The rain garden (above left) captures temporarily stored water delivered by the dry creek bed and provides a pleasant aesthetic amendment and functions to keep stormwater onsite
- Earthcraft Landscape Design Cistern Project, Scotts Valley, California
The Earthcraft Landscape Design company designed this installation project including a 30,000 gallon rainwater harvesting system.
- Reduced erosion and peak flows, resulting in reduced sedimentation into Granite Creek
- New water supply meets all of watering needs for the extensive organic garden on the property
- Rain Garden, Watsonville, California
This rain garden/retention pond has been implemented on the Smith and Vandiver parking‐lot area company. The rain garden helps reduce peak flows, keeping runoff onsite and treats the runoff as it filters through the soil.
- Vegetated Swale, Watsonville, California
The Strawberry Business Center has incorporated into their parking area this vegetated swale to manage stormwater like natural drainage system. Runoff is conveyed slowly over the permeable surface of the swale, allowing sediment dropout and infiltration of the polluted runoff.
- Vegetated Swale, Watsonville, California, continued
- Pervious Hardscape, Santa Cruz California
This residential retrofit involved replacing a cement walkway with a pervious walkway. The broken pieces of removed cement were reused as the foundation for the new pervious walkway. Two downspouts from the house were redirected towards the excavated pathway to keep stormwater onsite and to prevent flooding.
- Pervious Driveway and Drought Tolerant Landscaping, Santa Cruz, California
This Santa Cruz resident replaced their previously impervious, cement driveway with a pervious‐paver driveway to allow infiltration of stormwater runoff from their roof and other surfaces. Thyme was planted in the middle of the pervious‐pavers. Pieces of concrete from the original drive were used to create stepping stone paths around the property, and some were used to create a small patio. The lawns in the front and back yard were replaced with drought tolerant plants, including Mediterranean varieties and some redwood forest groundcover species in damp areas.
- Retrofitted Home and Property, Los Angeles, California
The Hall house in Los Angeles is an example of a thorough home and landscape retrofit. The component Best Management practices involve a range of techniques from infiltration to rainwater harvesting to vegetated swale conveyance.
- Integrated approach:
- A connected rain‐harvesting system composed of two 1,800 gallon tanks and a first‐flush diversion device divert the most polluted water in the first storm
- A vegetated/mulched swale which receives lawn trimmings a means to further enhance the sedimentation and infiltration process
- Retention grading or bermed landscaping to keep stormwater onsite, promoting groundwater infiltration
- A drywell implemented into the driveway; collects runoff in a trench filled with crushed rock and sand and prevents stormwater from entering the street