The Hazel's Creek Drainage & Conservation Facility is a regional stormwater management project that serves a large portion of the South Hill.
The facility also serves as a demonstration site for a number of low-impact development (LID) techniques and as a passive recreation and wildlife area. The site includes detention and infiltration ponds, enhanced wetlands, and pedestrian paths, among other features.
The Hazel's Creek site is located in a natural drainageway and supports a small stream—Hazel's Creek. In the past, two small farms were built on the property. The red barn is the remaining landmark of these farms. The creek is named for the last owner and resident, Hazel O'Byrne.
Water shaped this land for thousands of years. A paleochannel, an ancient creek bed buried during the Missoula floods, begins at this site. Hazel's Creek flows into that channel.
Check out this great video on the story of Hazel's Creek.
For more information on Hazel's Creek, see:
Pervious concrete is located in three places at the Hazel's Creek site. These surfaces are similar to their standard pavement but with less fine material like sand. As a result, openings form between the rock in the pavement and allow water to infiltrate. This Low Impact Development technique produces less runoff because rain water infiltrates where it falls. Permeable pavements can be used in driveways, parking lots, sidewalks, and bike trails, and can add an attractive addition to a home owner's yard. Patios and sidewalks are great places for pervious concrete or PICP. When installed correctly, permeable pavements will reduce runoff.
Types of permeable pavements:
A storm garden is a vegetated depression that stores, treats and infiltrates stormwater runoff. A combination of amended soils, plants, and plant root systems is effectively used to both store and treat stormwater directed the storm garden. Water from the storm garden that is not evapotranspirated by the plants will gradually infiltrate in to the ground, eventually recharging our aquifer.
Storm gardens have many benefits in addition to managing stormwater. They can be incorporated into a site's overall landscaping to provide shade, create wind breaks, absorb noise, improve an area's aesthetics, and reduce irrigation needs. Storm gardens are also less expensive to maintain than lawn areas or grass swales. Does your yard have a “wet spot”? Where does your roof drain? These are examples of some areas that can become storm gardens.
Rainwater reuse reduces the amount of stormwater runoff on a site. Rainwater collection systems are designed to collect and store runoff from impervious surfaces such as roofs, paved terraces, and patios. The water collected by these systems may be reused for non-drinking water uses. Possible uses include:
Design your landscape to make the most of the rainwater collected from impervious features. Consider using a rain barrel; learn how to make one by visiting Mike's Garden Blog.
Drought-tolerant plants are an important part of low impact development techniques. An efficient planting design uses less water, fertilizers and pesticides, but it also takes less time to maintain. To achieve an efficient design, plants must be grouped by sunlight needs, the water they require and conditions of the soil. Other considerations are how the plant will respond to Spokane's precipitation patterns of wet springs and dry summer. Replacing turf grass with drought-tolerant plants may require less time and money to keep looking great for many years. You can find a list of drought tolerant plants for Spokane in the links. It is important to not over fertilize or over water your turf grass to protect water quality in the Spokane River and the Aquifer.
In both a storm garden and a home garden mulches can:
The goal of low impact development techniques is to manage stormwater at the site. This means the soil must be able to infiltrate, or soak in, the runoff that comes to it. Soils on developed sites are often compacted so they let water runoff instead of infiltrating. In addition, healthy soils will trap sediments and contaminants. Compost, sandy loam or pH adjusters may be added to improve the soil heath and allow it to infiltrate runoff. Mixing home-made compost into the soil is a way to amend the soils at your home. Compost can be added at a 2:1 (soil to compost) ratio.
The wetland on Hazel Creek site covers about 5 acres and is part of a slightly larger system where groundwater comes to the surface. The wetlands act as a catchment basin for local stormwater, and receive water from seeps and drains located along adjoining hillsides. During large storms, runoff may overflow to the creek and then into the wetlands. The wetlands provide treatment for this runoff. Wetlands are compared to the earth's kidneys because they help control water flow and clean the water going through just like kidneys in people and other animals. Wetlands are important to water quality and stormwater runoff to:
Prior to the City's purchase, the site was used for a small farm with pastures, fruit trees and gardens. The creek was diverted to flood the pastures in the summer to water. The spring was also used to make ice in the early part of the 1900s. The City purchased the land beginning in 2004 for use as a stormwater facility and removed all of the buildings except the red barn. The creek has been named in honor of the last resident, Hazel O'Byrne.
Constructing a building causes impacts to the immediate environment. Excavation for foundation severs roots and destroys plants, the movement of heavy equipment compact the soil, and this results in ground that is more likely to cause erosion and less able to infiltrate and treat stormwater runoff. A foundation that had minimal disturbance to the soil would protect water quality because when the top soil is kept in place, the natural ability to infiltrate and store is preserved. Runoff from the roof and surrounding areas will continue to infiltrate without any manmade interference. Pin Foundation, an innovative system developed and patented by Pin Foundations, Inc. of Gig Harbor, Washington, is one example of a way to build a foundation without excavation. This system provides infiltration and subsurface water storage that would otherwise be lost from construction of a conventional “dug-in” foundation system.
For further information on the design and use of this technology contact Pin Foundations, Inc. at 253.858.8809 or visit their website
Grassed filter strips are also known as vegetated filter strips, vegetated buffers, and grassed filters, are vegetated surfaces that are designed to treat stormwater runoff and sheet flow from adjacent surfaces. Filter strips function by slowing runoff and allowing sediment and other pollutants to settle, and then infiltrate into underlying soils. Filter strips were originally used as an agricultural treatment practice and have more recently evolved into an urban practice. With proper design and maintenance, filter strips can provide relatively high pollutant removal. In addition, the public views them as landscaped amenities and not as stormwater infrastructure. Consequently, there is little resistance to their use.
When rain falls or snow melts on natural ground, some of the water soaks into the ground, or infiltrates. Pavement and roofs are called impervious surfaces because water cannot infiltrate. Any impervious surface can create stormwater runoff. Some examples of impervious surfaces include streets, parking lots, sidewalks, compressed soils, roofs, or overwatered lawns. Rain or melting snow on impervious surfaces causes stormwater runoff. Too much runoff can cause flooding.
As stormwater flow across impervious surfaces, it picks up contaminants. Although there may not be a lot of pollutants in an area, as the runoff from many areas come together, the amount of pollutants increase. The increase in concentration of contaminants causes pollution. Pollutants in stormwater may include:
Stormwater management is the practice of controlling the quantity of runoff to prevent flooding and to remove pollutants to protect the water quality in rivers, streams and ground water. Best Management Practices (BMPs) are method used to prevent or reduced stormwater pollution. Low Impact Development BMPs reduce stormwater runoff and treat it at the site. How can you protect stormwater and aquifer quality?
Noxious weeds are non-native plants that have been introduced through actions by people. Because the plants are not native to Spokane, they have no natural enemies to keep them from growing out of control. Sometimes these plants are called invasive because they “invade” or “take over” by growing rapidly and out-competing native plants.
Noxious weeds have been brought to Spokane through accidental and intentional human activities. These plants have transported from faraway places like Europe, Asia or Africa with similar climate. Some are brought as ornamentals plants, or planted as forage crops. Seeds can be spread by animals, humans, water and wind. Seeds can go in the planter mixes, nursery plants, or contaminated seed. Once established, weeds produce a lot of seeds, or can grow new plants from the roots.
Any place were ground is disturbed by construction or replanting or worn down, weed seeds can be exposed and will grow.
Problems caused by Noxious Weeds:
Like many areas in Spokane, land is altered by human activities. Some activities modify the flow of water, damage the soil, introduce noxious weeds, and pollute our water. We can help restore the land by planting native vegetation, amending the soil, and treating stormwater runoff.
Streams in this part of the Moran Prairie were formed by runoff from Brown's Mountain. The historic Missoula floods filled stream channels with gravel and sand, and this created underground streams called paleochannel. Water has always attracted people and animals. This creates an environment ripe for activity. Hazel's Creek, prior to European contact, was once utilized by the Spokane Indians. The Spokane belong to the Interior Salish language family and ethnographically consists of three bands: The Upper, Lower, and Middle Spokane. The Lower Spokane settled around the Little Falls area, the Middle Spokane in the Hangman (Latah) Creek area, and the Upper Spokane around the Little Spokane River and upriver from Hangman Creek.
The Spokane Indians were hunter-fisher-gatherers. Both short term and permanent settlements were strategically located to enhance the exploitation of surrounding resources. The Spokane had a complex and streamlined fishing technology for the exploitation of the once abundant riverine resources. Furthermore, plants were a major food source, they were diverse, predictable and easy to process and store. Native plants made up as much as half of the subsistence resources utilized by the Spokane Indians.
Today, the Spokane Indians persevere and adapt, living in two worlds. Spokane Indians are actively protecting and preserving aspects of their language, culture, and heritage. Spokane Indians are not part of the past; we are still here – in the present.
When water hits subsurface bedrock, the water is unable to infiltrate into the aquifer and flows laterally through the soil to wetlands, water bodies, or to fractures in the bedrock that allow it to infiltrate to the aquifer. Where bedrock below the surface is shallow, the soil can become very wet and soggy. In Hazel's Creek there are many areas like this. In order for the water to escape, soil connectivity needs to be maintained. When impervious surfaces are constructed and soil is removed, this connectivity is disrupted and can result in water being redirected or pooling in an area. These can have adverse affects on vegetation and wildlife. It can also impede stormwater treatment and dispersion, resulting in poor water quality or unusable land area. It can also cause flood damage for City infrastructure and property owners.
Because the majority of natural wetlands and the natural hydrology of the area have been altered, it is important to preserve groundwater interflow and replicate pre-development conditions whenever possible. Your neighborhood was previous a patchwork of alternating dry and wet areas. Rainwater was shed from high spots in the landscape and drained to channels that became streams, creeks, and rivers. It also drained to low spots and depressions that became wetlands. Today, using storm gardens and permeable pavement, and minimizing total soil disruption, as this portion of trail does by being built up on the soil rather than carving through it, helps to preserve and/or emulate the existing water cycle and improve water quality.