Restoring Paradise in Moscow, Idaho
by Amanda Cronin
Paradise Creek Restoration site and a sea of blue tube tree protectors.
Improving our Home Watershed: Paradise Creek
Paradise Creek is located in the Palouse Basin. The Palouse River is a tributary to the Snake River, the largest tributary to the Columbia River in the Pacific Northwest. Originating from Moscow Mountain (elev. 4,983 ft.), in Latah County, Idaho, Paradise Creek flows southwest for 20 miles, through Moscow, Idaho (elev. 2,520 ft.), ultimately entering the South Fork of the Palouse River in Pullman, Washington. Average annual precipitation is 24 inches in Moscow, mostly occurring as snow or rain in the winter months. Paradise Creek drains 34 square miles, and is comprised of 55 stream segments, of which 49 flow through agricultural fields. Wetlands associated with riparian areas along Paradise Creek are in poor condition due to past and present management activities such as draining and tiling. In late winter and early spring, melting snowpack and rain fall onto frozen soils causing peak runoff and flood events, with the largest event approximately 1,000 cfs. During periods of low flow, in the summer, effluent from the Moscow Wastewater Treatment Plant (MWWTP) contributes more than 90% of the flow in Paradise Creek downstream of Moscow.
Cropland is the most prevalent land use (approximately 73%) in the Paradise Creek Watershed, but provides the least diverse plant community type. The lack of multi-story riparian vegetation is probably the most limiting factor to restoring a diversity of wildlife species and available habitat in the watershed. Over 240 species of wildlife are seen in our watershed, including elk, moose, mink, bobcat and cougar, with the greatest diversity found in birds. Over 160 species have been observed, including bald eagles, warblers, long-eared owls, peregrine falcons, and Rufous and Calliope hummingbirds. Historically, Paradise Creek supported cold water fisheries. Currently, the creek only supports limited pollution tolerant fish species; Redside Shiner, Speckled Dace, Northern Squawfish, Columbian Largescale Sucker and Longnose Sucker.
Today, Paradise Creek is a simplified ecosystem impacted by habitat destruction, excessive sediment, nutrients, high temperatures, altered flow, pathogens and ammonia, which combined, have significantly decreased its biological integrity and impaired its beneficial uses. Negative impacts on the stream continue to increase along with growth in the urban areas of Moscow and Pullman, so that it is becoming even more difficult for the creek to repair itself.
In 1994, PCEI received Phase One of the Paradise Creek Watershed Restoration grant from the IDEQ and Environmental Protection Agency under section 319 of the Clean Water Act. This was to restore the floodplain and streambanks at a site owned by the Moscow School District, and to develop an erosion control ordinance for the City of Moscow (see article in Land and Water May/June 1997). Currently, we are in the process of completing Phase 7, of Paradise Creek watershed restoration, also supported by IDEQ, which calls for the implementation of nonpoint source controls to achieve Total Maximum Daily Load (TMDL) allocations, as outlined in the TMDL Implementation Plan, written by the Paradise Creek Watershed Advisory Group in 1999. The project includes: animal waste prevention and treatment wetlands, revegetation of riparian areas in the urban and agricultural environment, streambank stabilization and agricultural land restoration in association with other local agencies and community partners.
East Mountain View Road Restoration Project
Prior to restoration, the 860 ft reach of stream channel had near vertical, eroding streambanks that were straightened and incised due to dredging activities. The banks were generally steep averaging between 1H:1V and 2H:1V. Streambanks were either exposed soil or covered with reed canary grass and other invasive weeds. Except for a few non-native willows, the site was completely devoid of riparian species to shade the creek. The reach flows from the east to the west at the site and the project boundaries were defined as a city road and bridge to the west, a public charter school upstream to the east, an apartment complex with a parking lot to the south and a house and horse pasture to the north.
Working with the City of Moscow and TerraGraphics Environmental Engineering, PCEI designed a restoration plan to increase the flood storage capacity of this reach by lowering the floodplain by two feet and constructing two major meanders, a narrow low flow channel, and associated wetlands. The constructed channel was intended to mimic natural conditions as much as possible. The lowflow channel was designed with a 3 foot bottom width and a depth of 1.5 feet. In addition, a revegetation plan was devised using exclusively native woody and herbaceous species of the Palouse Basin. Approximately two and a half acres of floodplain were created. The goals of this project were ecological as well as societal. PCEI aimed to reduce listed non-point source pollutants (sediment, bacteria, temperature, and nutrients) in Paradise Creek by decreasing sediment delivery through the installation of shallow wetlands. We also planned to reduce instream erosion by stabilizing severely eroded streambanks and to improve aquatic and riparian habitat by vegetating with native plants. This was fundamentally a community based restoration project, designed to raise citizen awareness about water resources and increase stewardship within our community, as well as provide a recreational, educational and aesthetic benefit.
The top of the stream channel bank was rounded off to make a smooth transition to the floodplain surface. All outside bank slopes were subsequently seeded with a native riparian grass mix and lined with 100% biodegradable geotextile fabric made of woven coir yarn. Erosion control fabric was installed over the top of the slope crown onto the level edge of the floodplain surface. A low density straw erosion control blanket (ECB) was used in lower energy areas and a high density coir fiber ECB was used in higher energy areas. The organic fiber geotextiles, coir logs, and ECBs will retain structural integrity for multiple growing seasons allowing time for the establishment of dense native herbaceous ground cover on all bank surfaces.
A portion of the excavated soil was used to fill in the existing channel, the remainder of the excavated soil (5,000 cu. yards) was moved off site and used by the City of Moscow and the local university.
Planting of over 1,500 woody trees and shrubs began with the second annual Paradise Creek Watershed Festival which included 10 classes of fourth graders from Moscow schools and University of Idaho volunteers. Under the supervision of PCEI staff, the bulk of the planting was completed during the following weeks by volunteers. The following woody species were integrated into the design: Quaking Aspen (Populous tremuloides), Dougles Hawthorn (Crataegus douglassi), Rocky Mt. Maple (Acer glabrum), Thinleaf Alder (Alnus incana), Red Osier Dogwood (Cornus stolonifera), Serviceberry (Amelanchier alnifolia), Syringa (Philadelphus lewisii), Chokecherry (Prunus virginiana), Nootka Rose (Rosa nutkana), Douglas Spirea (Spirea douglasii), Common Snowberry (Symphoricarpos albus) and Ponderosa Pine (Pinus ponderosa). Our budget allowed us to focus the planting on larger nursery stock; the majority of woody plants were one, two or five gallon sizes. As is the procedure at all our restoration sites, all woody plants (with the exception of conifers) are protected from rodent damage and browse by 18 inch blue plastic tree protectors, secured in place by bamboo stakes. Ponderosa pines on site had shorter 6 inch tubes around their base.
Herbaceous plants included: Water Sedge (Carex aquatilis), Creeping Spikerush (Elocharis palustris), Baltic Rush (Juncus balticus), Common Rush (Juncus effuses), Daggerleaf Rush (Juncus ensifolius), and Small-fruited bulrush (Scirpus mircocarpus). A total of 1,140 herbaceous plants were planted in 10 cubic inch sizes. Plugs were inserted in the coir logs using a dibble. In the areas without coir logs, herbaceous plants were placed along the stream banks, keeping in mind the ecology of each species. In addition to the nursery plugs, PCEI staff, interns and volunteers transplanted seventy Blue Flag Iris bulbs (Iris missiouriensis). These bulbs were dug up and stored in pots during the Summer 2002 construction season.
Planting at this restoration site will continue into Spring 2003. The bulk of this will be native willow cuttings planted near the top of all streambanks and around the wetlands, especially focusing on potentially unstable areas. Eventually willows, Red Oiser dogwood and other species will provide intertwining root networks for long-term bank stabilization in these areas. Willow cutting will be planted using a hydraulic stinger, which consists of a 5 foot 1 inch diameter pipe that is connected to a water pump, and used by inserting it into the ground to make a hole for each cutting. Cuttings are planted so that 1/3 of the plant is above ground and 2/3 below ground.
In December of 2002, we observed some small rills forming near the top of the outside, upstream meander bend. The rills were forming as a result of standing water in the floodplain and probably exacerbated by impervious surfaces adjacent to the project. We were concerned about the erosion undermining the stability of the rootwad revetment and erosion control fabric below. So, on the morning of our first snow we rented a mini excavator, dug out the problem area, and placed cobble and boulder sized rocks in the depression. Moscow has been experiencing a mild winter with lower than average snowfall and we expect this trouble section to remain stable.
Our first high water event occurred after 3 inches of rain over two days at the end of January 2003. The creek swelled to the top of the new channel and flowed overland in much of the floodplain. After the water subsided, all revetments and plants remained intact.
Overall we are pleased with the success of this restoration project and we are especially appreciative of the community support it has enjoyed. As is the nature of land rehabilitation, the primary determining factor is time in achieving habitat and stabilization goals. We are eager to watch this project grow and become a sustainable natural system within the City of Moscow. The extent to which the stated objectives were met will be evaluated through further monitoring efforts by PCEI, the University of Idaho and additional project partners. Use of the term restoration is debatable, since we are not truly restoring this piece of ground to a former more pristine state. Rather, we are attempting to restore the functions of the creek by providing a functioning floodplain and associated wetlands, a diverse meandering stream channel, and native Palouse Basin habitat in a setting that has much public benefit.
For more information contact Amanda Cronin, Watersheds Program Coordinator, Palouse-Clearwater Environmental Institute, P.O. Box 8596, Moscow, Idaho 83843, (208)882-1444, fax (208)882-8029, e-mail: email@example.com, web site: www.pcei.org.
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