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Stormwater Management

Stormwater management is the strategic process of handling precipitation that does not immediately soak into the ground during weather events. While commonly associated with rainfall, this form of watershed management also addresses runoff generated by melting snow, especially in urban areas where impervious surfaces prevent natural absorption.

The primary aim of stormwater management is to control and direct excess water in ways that prevent property damage and promote sustainable reuse. By effectively managing runoff, communities can reduce the impact of sudden water surges on infrastructure and natural ecosystems.

There are several compelling reasons why stormwater management is vital to environmental health. One major benefit is the reduction of soil erosion. Uncontrolled runoff can wear away layers of soil, weakening building foundations and rendering agricultural land unsuitable for crops. By redirecting and slowing down water flow, stormwater systems help preserve soil integrity and protect valuable land from degradation.

Another significant advantage is pollution control. As runoff travels over surfaces like roads, parking lots, and lawns, it can collect harmful contaminants. Without proper management, this polluted water may flow directly into rivers and lakes, disrupting aquatic ecosystems. Modern stormwater systems are often designed to capture and treat this water, filtering out pollutants before the water is released back into the environment. This treatment helps maintain the ecological balance of our waterways and supports healthier, more resilient ecosystems.

Stormwater management plays a crucial role in protecting both the built and natural environments, making it an essential component of sustainable urban planning and environmental stewardship.

Indian Creek Watershed Management Authority

Persistent flooding and water quality concerns have led the governmental entities within the Indian Creek watershed to embrace a cooperative, multi-jurisdictional planning approach. The resulting Indian Creek Watershed Management Plan details strategies and recommendations for watershed and stormwater management, water quality protection, and stormwater permit compliance. It includes specific implementation strategies and milestones for implementing these recommendations for local governments as well as regional and state agencies. Roughly 25% of Hiawatha’s land area is in the Indian Creek watershed.

Middle Cedar Watershed Management Authority

The Middle Cedar Watershed Management Authority (MCWMA) was formed as a result of a nearly $97 million grant awarded to the State of Iowa from the US Housing and Urban Development under the title, "Iowa Watershed Approach" (IWA). The MCWMA is filed through the State under a 28-E agreement its members consist of Cities, Counties, and Soil and Water Conservation Districts. Members of the MCWMA work collectively together to address water quality, quantity, as well as other environmental issues that cross jurisdictional boundaries through the Middle Cedar Watershed Management Plan. Roughly 75% of Hiawatha’s land area is in the Middle Cedar watershed.

What is Stormwater Infrastructure?

Stormwater is the runoff from rain or snowmelt that is not absorbed by soil. Stormwater infrastructure is any element that helps transport that runoff, such as:

  • Storm intakes
  • Underground storm sewer pipes
  • Drainageways
  • Culverts
  • Detention/Retention basins

It is important that current stormwater and drainage infrastructure be adequately maintained and/or improved to meet Hiawatha’s projected growth rate.

Erosion and Sediment Control

Construction activity is one of the leading contributors to sediment entering waterways. This impact is largely due to several factors: the exposure of bare soil to stormwater runoff, increased runoff volume, and changes in surface water patterns that can disrupt drainage systems, destabilize slopes, and damage existing vegetation.

To mitigate these effects, construction sites must follow erosion and sediment control practices as required by local, state, and federal regulations. Proper site management plays a critical role in minimizing soil erosion and preventing sediment from being transported off-site.

Erosion control measures serve as the first line of defense. By preventing the soil from eroding in the first place, there is less need for downstream sediment control. However, even with the best intentions, most construction projects will expose bare soil at some stage. To limit the movement of this soil and protect nearby water resources, a variety of techniques are employed—including diversion dikes, silt fences, and sediment basins. These practices help contain runoff, capture sediment before it leaves the site, and preserve the integrity of the surrounding environment.

Effective erosion and sediment control is not just a regulatory requirement—it's a vital part of sustainable construction that safeguards ecosystems, infrastructure, and community health.

Illicit Discharge

An illicit discharge is defined as any discharge into a municipal separate storm sewer system (MS4) that is not composed entirely of stormwater—except for discharges permitted under a National Pollutant Discharge Elimination System (NPDES) permit or those resulting from emergency firefighting activities. These unauthorized discharges often originate from illegal or improper connections to the storm drain system, particularly from commercial or industrial establishments.

As a result of these illicit connections, untreated and potentially contaminated wastewater can flow directly into storm drains or nearby waterways, bypassing wastewater treatment facilities entirely. This can lead to serious water quality issues and pose risks to public health and the environment.

Illicit connections may be deliberate or exist without the knowledge of the property or business owner. A common example is a floor drain mistakenly or unlawfully connected to the storm drainage system. Other sources of illicit discharges include failing septic systems, illegal dumping of waste materials, and the improper disposal of sewage from recreational activities such as camping.

Preventing and eliminating illicit discharges is essential for protecting water quality and maintaining the integrity of local ecosystems. Public awareness, routine inspections, and compliance with stormwater regulations are key components in addressing these harmful practices.

Illicit Discharges Include:

  • bacterial growth
  • blood
  • chromium
  • construction sites
  • debris
  • foam
  • industrial discharge
  • iron and other metals
  • oil
  • paint
  • rinse water
  • septic flow
  • sewage
  • suds
  • toilet paper
  • toxic chemicals

To Report an Issue

If you would like to report illegal or illicit discharges of non-storm water or non-irrigation runoff to the stormwater system, please call the City of Hiawatha Stormwater Hotline at (319) 393-1515 or submit this online form.

Best Management Practices (BMPs)

The City of Hiawatha is encouraging and utilizing Best Management Practices (BMPs) as described in the SUDAS Erosion and Sediment Control Manual. There is a lot that can be done to help mitigate stormwater pollution, which can be caused by anything ranging from improper disposal of hazardous materials to overuse of lawn care products. Common sources of pollution include: batteries, fertilizers, household cleaners, motor oil, painting materials, pesticides and pet excrement. For information regarding acceptable practices and designs refer to iowasudas.org, ctre.iastate.edu or the Iowa Rain Garden Design and Installation Manual.

Stormwater Runoff & Local Awareness

Stormwater runoff from residential properties can pick up pollutants such as lawn fertilizer, pet waste, and trash, and carry those into storm sewers, creeks, and rivers. Below are some methods that can be used to improve the quality of storm runoff and improve our local streams and lakes. These methods can be used to capture and infiltrate stormwater in residential areas. Stormwater BMPs such as rain gardens, rain barrels and soil quality restoration can be used in residential yards to capture stormwater where it falls and allow it to infiltrate into the ground.

  • Rain gardens are shallow depressions that contain permeable soils and native plants where rain water is collected from yards and downspouts. Rain water is then taken up by the roots of the native plants and also naturally infiltrates into the earth. Maintenance for Rain Gardens include:
    • Water for the first year and during droughts.
    • Inspect for vegetation disease or pest problems. Replace vegetation as necessary.
    • Remove weeds as necessary, especially the first couple of years during plant establishment.
    • Remove dead vegetation at least once a year.
    • Inspect after major storms for debris and sediment, and repair any erosion.
    • Remove trash, debris, and sediment as necessary.
    • For rain gardens, protect the outlet and repair when necessary.
  • Soil Quality Restoration (SQR) is a simple but effective way to improve the ability of lawns to absorb rainwater. A process of soil aeration and compost application improves the root systems of lawn grass and allows for better rainwater absorption.
  • Pervious pavers are a great way to add a hardscaped area to your yard while simultaneously reducing the amount of stormwater runoff leaving your home. Pervious pavers are a combination of pavers that let water go through them and an underground layer of rock that acts as a temporary storage area for rainwater.
  • Native Plants are plants originally found on the Iowa landscape. These plants typically have deep roots that improve rain infiltration. Native plants generally need less fertilizer and irrigation than standard turf and provide an important food source for pollinators. Maintenance for Native Plants include:
    • Water for the first year and during droughts.
    • Inspect for vegetation disease or pest problems. Replace vegetation as necessary.
    • Remove weeds as necessary, especially the first couple of years during plant establishment.
    • Remove dead vegetation at least once a year.
    • Inspect after major storms for debris and sediment, and repair any erosion.
    • Remove trash, debris, and sediment as necessary.
  • Trees help intercept rainwater before it reaches the ground and becomes runoff. They also cool down hot surfaces which reduces thermal pollution from stormwater.
  • Rain barrels collect rain water from roofs and downspouts. This water can then be used to water plants, gardens, lawns, or even for flushing toilets. The Iowa Stormwater Education Partnership has created an informational video on building your own rain barrel.
  • Green roofs are systems that incorporate living plants, soil media, and drainage layers on top of conventional building structures. By capturing rainfall where it lands, green roofs help reduce stormwater runoff volumes and improve water quality. They also provide insulation, extend roof lifespan, reduce the urban heat island effect, and offer habitat and aesthetic value in dense urban areas.
  • Bioretention cells are engineered landscape depressions that capture, filter, and infiltrate stormwater runoff from impervious surfaces like roofs, driveways, and parking lots. These versatile stormwater management features can be incorporated into most settings, including commercial, residential, and municipal areas. Bioretention cells are particularly valuable in locations where existing soils don’t adequately drain, as they include carefully designed layers that enhance infiltration and pollutant removal.

Help Keep Our Water Clean

Stormwater runoff from your street, sidewalk and driveway flows directly through storm drains and ditches to streams, wetlands, and lakes. This runoff washes pollutants into surface waters harming water quality and fish habitat.

Your everyday activities can help preserve the health and well-being of nearby waters like Dry Creek, Ushers Ferry Creek, and Otter Creek. Below are some tips to help prevent water pollution from runoff:

  • Sweep you walks and driveway instead of hosing them down. Soil, grit and debris from paved surfaces often contain contaminants that pollute water.
  • Wash your vehicle on grass or gravel areas to prevent wash water from running into storm drains. Wash water can contain oils and detergents that harm water quality.
  • Maintain your vehicle regularly. Oil leaking from vehicles contains toxic metals. Rain picks up these materials and carries them to area streams, lakes, and wetlands where they pollute water and harm fish.
  • Recycle used motor oil and dispose of household hazardous waste properly. Never dump oil or other hazardous wastes down a storm drain or pour it on the ground.
  • Use safe, non-toxic solutions to manage plant problems. For information about effective ways to manage pests with toxic chemicals, call Iowa State University Extension and Outreach at 319-377-9837.
  • Preserve vegetation. Plants filter pollutants from runoff, and prevent erosion. Plants near waterways provide habitat for fish and wildlife and shield streams from extreme temperatures.
  • Control animal access to streams. Animal wastes degrade water quality and livestock can trample and erode stream banks.
  • Buy low-phosphate detergents.
  • Place trash in the garbage.

Resources

  • IAMU - Iowa Association of Municipal Utilities
    With the mission to support and strengthen Iowa's municipal utilities, IAMU represents more than 550 municipal electric, gas, water and broadband utilities in the state.
  • Iowa Stormwater Education Program
    Provides education, outreach, technical resources and training programs to protect and improve water quality in Iowa.
  • Rainscaping Iowa
    A statewide educational campaign that promotes urban storm water management practices to protect water quality and reduce runoff.
  • Interactive Water Cycle Diagram for Kids
    The water cycle describes how the Earth's water changes from liquid (rain), gas (vapor), and solid (ice), as well as how it moves around the Earth. The water cycle is a continual process that does not stop.
  • Concrete Washout and Dewatering
    Concrete washouts and dewatering are both related to construction site management and environmental protection, particularly regarding water pollution and runoff control.

City Ordinances

Contact

For questions or concerns regarding any stormwater related issue, please call the City of Hiawatha Stormwater Hotline (Community Development Department): 319-393-1515.

If you would like to report illegal or illicit discharges of non-storm water, non-irrigation runoff to the stormwater system, please use either the online form or our printable form.

Helpful Links