What is stormwater run-off?

Stormwater run-off is the water that flows over land after rainfall or snow melt.

Why is stormwater a problem?

Under natural conditions, most stormwater is absorbed into the ground. The remaining stormwater run-off slowly flows across forests and meadows before entering streams and rivers.

Land use and development can significantly alter the timing, quantity, and quality of runoff entering our local streams and rivers.Developed areas are often largely impervious, preventing stormwater from naturally entering the soil and recharging groundwater. This results in more stormwater run-off moving quickly across the surface, which developed areas have to manage by storm sewer systems and ditches designed to convey stormwater in concentrated flows. This allows large volumes of stormwater to quickly enter our waterways from a pipe or ditch outfall. Water levels in streams rise more quickly in response, leading to flooding in some cases. In addition, fast-moving stormwater can cause erosion and will pick up pollutants such as oils, fuels, fertilizers, pesticides, dog poop, and garbage as it flows across developed surfaces.

What you should know about stormwater in Juneau?

In Juneau, everything dumped on the ground or into a storm drain ends up in our waterways, eventually flowing into Gastineau Channel.

Five anadromous and resident fish streams in the urban Juneau area are currently on the State of Alaska list of impaired or threatened waterbodies, and stormwater has been identified as the major contributor to the impairment of four of these watersheds: Duck Creek; Jordan Creek; Lemon Creek; and Vanderbilt Creek. To learn more about Juneau's impaired watersheds visit DEC's Juneau Watersheds page.

Photo: Stormwater entering Jordan Creek.

What is a BMP?

BMP stands for "Best Management Practice," and it refers to measures that are taken to improve stormwater quantity or quality. There are generally two types of BMPs: structural and non-structural.

Structural BMPs such as swales, detention ponds, oil-water separators, catch basin inserts, require installation and, in some cases, design work by an engineer. Some structural BMPs are referred to as green infrastructure.

Non-structural BMPs include "good house-keeping" behaviors, as well as approaches to minimize stormwater impacts without having to install structures.  This includes but is not limited to picking up garbage, quickly responding to oil or fuel spills, minimizing or eliminating the use of fertilizers or pesticides, leaving natural riparian buffers, and minimizing disturbance during construction to name a few.

The City and Borough of Juneau (CBJ) has a Manual of Stormwater Best Management Practices that address post-construction stormwater from new development or redevelopment.

10 Things YOU Can Do to Prevent Stormwater Runoff Pollution:

You can help be the solution to water pollution by reducing the amount of chemicals and other pollutants in your yard and home.

    1. Use fertilizers sparingly and sweep up driveways, sidewalks, and gutters.
    2. Never dump anything down storm drains or in streams.
    3. Vegetate bare spots in your yard.
    4. Compost your yard waste.
    5. Use the least toxic pesticides, follow labels, and learn how to prevent pest problems.
    6. Direct downspouts away from paved surfaces and consider a rain garden to capture runoff.
    7. Take your car to the car wash instead of washing it in the driveway.
    8. Check your car for leaks and recycle your motor oil.
    9. Clean up after your pet.
    10. Have your septic tank pumped and system inspected regularly.

Learn more about what JWP has been doing to improve stormwater management:

The Juneau Watershed Partnership promotes development of efficient and adequate stormwater conveyance and treatment for the protection of water quality and quantity in Juneau's anadromous and resident fish streams. Here are some of our current and past projects to improve stormwater management in our community.