Privately Owned Stormwater Controls

Living in Iowa comes with the risk of occasional flooding from stormwater. In the urban and residential areas of Des Moines, the large amount of impervious surfaces lead to greater amounts of stormwater runoff and less detention and infiltration. City projects have been underway to help address this issue by expanding the sewer system in order to increase its capacity, building more protective measures such as levees and pump stations, and installing stormwater best management practices (BMPs). However, you may have a privately-owned stormwater management practice on your property. If you have a privately-owned structural control on your property and there is no existing contract or association that maintains it regularly, you as the property owner are required to maintain that practice in accordance with section 106-136 of the City of Des Moines Municipal Code. The City of Des Moines has provided the guides below to assist with maintenance of stormwater management practices on private property.  

Below is more information about specific BMP structures and a corresponding maintenance packet to follow once the BMP is installed so that it remains effective.

Stormwater Storage

Bioretention Cell
A bioretention cell, or rain garden, is a common form of green infrastructure which may look like a garden but is designed to capture stormwater from impervious surfaces like parking lots, roads, and buildings to be cleaned by natural biological processes. For more information on how to maintain your bioretention cell check out the Bioretention Cell Maintenance Packet.
Dry Basin
A detention basin is a stormwater best management practice (BMP) that is designed to control the flow of water during rain events, lessening the intensity of stormwater runoff. This helps minimize flooding and streambank erosion downstream. Additionally, by detaining stormwater the basin allows for sediment and other pollutants to settle out of the water. The health of local waterways and ecosystems benefit from this, so to ensure these continued benefits, proper maintenance of the detention basin is vital. For more information on maintaining your detention basin check out the Detention Basin Maintenance Packet.
Cistern
A groundwater recharge pit is a stormwater best management practice (BMP) that is designed to control the flow of water during rain events, lessening the intensity of stormwater runoff. This helps minimize flooding and streambank erosion in local creeks as well as further downstream in the drainage basin. Additionally, by detaining stormwater, the basin allows for sediment and pollutants to filter out of the water. The health of local waterways and ecosystems benefit from this, so to ensure these continued benefits, some maintenance is required. For more information on maintaining your groundwater recharge pit check out the Groundwater Recharge Pit Maintenance Packet.
Storm Chamber
A stormwater chamber is a stormwater best management practice (BMP) that is designed to control the flow of water during rain events, lessening the intensity of stormwater runoff. This helps minimize flooding and streambank erosion in local creeks as well as further downstream in the drainage basin. Additionally, by detaining stormwater, the basin allows for some sediment and pollutants to filter out of the water. The health of local waterways and ecosystems benefit from this. To ensure these continued benefits, some maintenance is required. Maintenance may be required when there is standing water around the area draining into the system. For more information on maintaining storm chambers check out the Storm Chamber Maintenance Packet.
Stormwater Separator
Stormwater separators are structures that are implemented to separate low density liquids and solids (e.g. oil, grease, some plastics) as well as high density solids (e.g. dirt, sand, degraded asphalt) from stormwater prior to it entering the storm sewer. It works most efficiently with lower flows and non-dissolved contaminants and is most commonly viable in high density, urban areas that don’t have the space for other Best Management Practices (BMPs). This low-maintenance, underground structure will result in cleaner water being discharged into receiving bodies of water. However, some maintenance will still be required to ensure the effectiveness of this BMP. To learn more about maintaining a stormwater separator check out the Stormwater Separator Maintenance Packet.

Stormwater Infiltration

Biofilter
A biofilter is a stormwater BMP used to capture harmful chemicals and sediment from surface runoff, cleaning the water with natural biological processes. The most common place to use a biofilter is in an urban setting, typically in a tree box filter where water can be directed through the filtration system. For more information on maintaining your biofiltration system check out the Biofilter Maintenance Packet.
Bioswale
A bioswale is a common form of green infrastructure which is designed to capture, redirect, and filter stormwater from impervious surfaces such as parking lots, roads, and buildings to be cleaned by natural biological processes. A bioswale is different from a bioretention cell or rain garden because it is designed to more purposefully redirect water and is less suited to retain standing water. For more information on maintaining your bioswale check out the Bioswale Maintenance Packet.
Green Roof
During a storm, water that falls on impervious surfaces such as roofs, roads, and parking lots never has a chance to penetrate the ground and soak back into the soil. This can result in what is known as an “urban heat island” which occurs do the lack of moisture exchange with the ground and the atmosphere. The concentrated flow produced during storms is also harmful to our waterways because of its erosive potential and the pollutants carried with it. A green roof is a stormwater management practice that aids in eliminating urban heat islands by storing water before releasing it back into the atmosphere via evapotranspiration by plants, while also filtering out pollutants before water leaves the area. For more information on maintaining your green roof check out the Green Roof Maintenance Packet.
Recharge Pit
A groundwater recharge pit is a stormwater best management practice (BMP) that is designed to control the flow of water during rain events, lessening the intensity of stormwater runoff. This helps minimize flooding and streambank erosion in local creeks as well as further downstream in the drainage basin. Additionally, by detaining stormwater, the basin allows for sediment and pollutants to filter out of the water. The health of local waterways and ecosystems benefit from this, so to ensure these continued benefits, some maintenance is required. For more information on maintaining your groundwater recharge pit check out the Groundwater Recharge Pit Maintenance Packet.
Native Landscaping
Urban landscapes have more impervious surfaces, such as streets, sidewalks, and parking lots, which decreases the ability for stormwater to infiltrate back into the ground. Additionally, urban soils are more likely to be compacted, further decreasing the infiltration capacity and increasing stormwater runoff.  Iowa’s historic prairie landscape dominated the state, created deep root systems that helped form rich soils high in organic matter. It was these rich soils that allowed for the absorption of most stormwater. The implementation of native prairie vegetation into developed areas will help reduce stormwater runoff and improve water quality for nearby receiving streams. By selecting species that will fit the moisture and sunlight conditions of your area, an aesthetically pleasing, ecologically beneficial landscape can be created. For more information on maintaining native landscaping check out the Native Landscaping Maintenance Packet.
Permeable Pavement
Permeable pavement materials are widely adopted as a stormwater best management practice (SWBMP) that are used to promote the infiltration and filtration of water into the underlying soil to limit the amount of contaminated runoff produced during rain events from entering our waterways. When traditional concrete or asphalt is used, it does not allow the infiltration of water, resulting in larger volumes of unfiltered runoff being discharged into streams, rivers, and other water bodies. The sharp increase in flow during rain events is the leading cause of erosion and one of the major contributors to aquatic pollution. These permeable materials consist of porous asphalt, porous concrete, and grass pavement systems which are most commonly implemented in parking lots, driveways, sidewalks, and low traffic roadways. For more information on maintaining permeable pavement check out the Permeable Pavement Maintenance Packet.