HoCo Residential Stormwater Management
Please note this website is not an official Howard County Government website. To learn more about the programs mentioned in this website and available through the Howard County Government, please visit: https://www.cleanwaterhoward.com/What is stormwater management and why does it matter?
Stormwater runoff is the only major source of water pollution still currently increasing in the United States. Pervious surfaces, such as grassy lawns and landscaped beds, are surfaces that allow water to pass through them and absorb into the ground. Impervious surfaces, such as concrete and asphalt, do not allow water to pass through them. Stormwater runoff picks up pollutants such as lawn fertilizers, motor oil, grease, trash, pesticides, dog waste, chemicals, sediment, debris, and other contaminants from the surfaces it washes over. If the water is allowed to flow directly into storm drains and thus waterways, it pollutes our local waterways including the Middle Patuxent and the Patapsco rivers, and eventually the Chesapeake Bay. Compared to water that falls on pervious surfaces, this stormwater is warmer and has more potential to cause erosion, both of which can harm water bodies' ecosystems and wildlife habitat.
When the average amount of impervious surface in a watershed is 10% or more there are significant negative impacts on water quality and habitat in waterways. You can help mitigate the effects of stormwater runoff and reduce pollution flowing through our local waterways by managing stormwater on your property! Scroll down to read some common negative effects of stormwater on Howard County residential properties and how you can take steps to address them.
Since this map was created in 2006, development in Howard County has continued to increase. Think about how much impervious surface is in your neighborhood today. What percentage of your property do you think is impervious surfaces?
Common Opportunities to Improve Stormwater Management
Ponding Water
Ponding or standing water is water that collects and stays on a lawn for over 24-48 hours. If you have a spot on your lawn that is lower in elevation than the rest and/or if you have a muddy/bare spot, you may have ponding water there when it rains. Check your lawn after a significant rainfall and note any places where water collects and stays for a while. Soil that is made of heavy clay and soil that has been compacted both have little room for water to pass through, preventing water from absorbing into the ground fast enough to keep up with the amount of runoff present during/after a storm.
Downsides of Ponding Water
Provides a place for mosquitoes to breed (takes 48-72 hours for mosquitos eggs to hatch)
Kills grass
Creates mud pets and people may bring into your house
Can be unsightly
Damage to surrounding infrastructure
Potential Actions
Taking care of water at the source, which is often downspouts
Regrading a lawn to change where the water flows
Planting native plants and trees to soak up and filter ponding water
Adding organic material (compost) to the soil
A combination of these actions
Erosion and Bare Soil
Erosion is when soil is lifted off the ground and taken somewhere else, often by water or wind. The soil picked up by stormwater runoff washes into storm drains then into local waterways and eventually into the Chesapeake Bay. Too much sediment (particles that settle at the bottom of waterways) buries habitats, disrupts food chains, clogs drains thus increasing the potential of flooding, and harms fish populations. Bare soil can easily be eroded, so it is important to keep soil covered. preferably with native plants!
Identifying erosion
Look for exposed roots and parts of structures like fence posts that should be buried. This may be a sign the soil has eroded away there. Bare soil is often eroded away. Mud collecting on sidewalks and streets is a common indicator. Also look for ditches, trenches, or trough in your yard that could indicate a path of erosion during rain.
Causes of bare soil
Frequent disturbances (kids playing, pets digging)
Shade
Ponding water (see above)
A combination of these causes
Potential Actions
Addressing the source of runoff which is often downspouts
Mulching and/or covering bare soil
A combination of these actions
Managing Plants
Plants are important for stormwater management because they filter stormwater and control erosion. Plants’ roots take up water and the plants filter and release the water into the air from their leaves. Their roots hold soil in place so it can not be eroded. Plants provide food, habitat, and a pollination source. for many native insects and birds. They can be aesthetically pleasing and filter the air.
Natives, Non-natives, and Invasives
Native plants have adapted over hundreds or thousands of years to the area they inhabit. They interact with other plants and animals in a complex web of relationships developed from adapting together. Non-native plants were brought to an area, often by people for food, medicine, or as decorative plants. Due to this, they have not evolved along with the rest of an ecosystem's species and thus can disrupt the greater habitat over time. Some non-native plants have characteristics that allow them to spread rapidly where they are introduced. These plants are known as invasive and they outcompete native plants, decreasing biodiversity and food/habitat for native animal species. They can cause all sorts of ecological problems and should be removed whenever they pop up. Both native and invasive plants can be classified as aggressive plants, which are fast-growing plants that outcompete other species. You should be aware of and monitor all aggressive plants, native or invasive, since they could take over your yard.
Not all non-native plants are invasive, but it is better to plant native plants in your yard because they are adapted to the area, should thrive if planted in the right conditions, and provide food/habitat that animals may not get from non-native plants.
It is important to manage plants in your yard. Do not plant invasive plants and remove them when you see them. For more information visit the Native Plants page. For more information on invasive plants, scroll down to the Invasive Plant section of the Native Plants page or the Resources page. Remember to manage your trees by keeping them free of vines and monitoring them for any problems that may require an arborist. Visit the Native Trees tab for more information.