The Tammany Creek watershed is situated on the eastern edge of the Columbia Basin, in the Palouse bioregion (Black et al, 2002). A second order tributary to the Snake River, Tammany Creek originates in the farmlands southeast of Lewiston in Nez Perce County, Idaho. Elevations of the stream range from 748-3500 feet. The main stem is 13 river miles long and drains 22,332 acres (about 35 square miles). With the exception of 75 acres on the Nez Perce Indian Reservation, the entire watershed lies within Nez Perce County (IDEQ, 2001).In the upper reaches of the watershed, the soils are dominantly Bryden and Endicott silt loams, resting on basalt from the Lolo flow of the Priest rapids member of the Wanapum basalt of the Columbia River group. In the middle and lower sections of the stream, the low relief topography of the higher plateau gives way to steeper slopes. Exposed basalt is present as are substantial alluvial deposits around the stream channel. Soils in the more northerly, lower elevation portion of the watershed are commonly Oliphant, Broadax, and Chard silt loams (IDEQ, 2001). Topsoil depths on cropland were originally between 20 and 25 inches, but erosion has reduced these depths by 20% to 50% (IDEQ, 2001).
Average annual precipitation ranges from 18 inches in the southeast of the watershed to 10 inches at lower elevations near the Snake River. The climate is mild relative to the rest of Idaho, with 140 to 180 frost free days (NPSWCD, 2002). July and August are hot and dry, with little rain, and temperatures over 100?F. Precipitation is fairly evenly distributed throughout the other 10 months of the year, and usually occurs in short duration and low intensity events (IDEQ, 2001). Most winter precipitation falls as rain, often falling on frozen soil, thawing the upper surface and creating rapid runoff on farmland soils. This winter rain and subsequent erosion accounts for a large portion of the sediment loading in Tammany Creek (NPSWCD, 2002).
Historically the watershed consisted of Palouse Prairie and canyon grasslands, with scattered shrub cover, and woody species such as willows (Salix) and black cottonwood (Populus trichocarpa) dominating the riparian zone. Nearly all of the pre-settlement vegetation has been converted to cropland, suburban development, or weedy annual species, and a multi-layered riparian zone exists along only 15% of the stream channel (NPSWCD, 2002). Consequently, peak flows and erosion have increased, and base flows, water quality, and diversity of aquatic life decreased (IDEQ, 2001).
Since 1900, 94% percent of the grasslands and 97% of the wetlands in the Palouse bioregion have been converted to crop, hay, or pasture lands. No quantification of riparian conversion has been completed?however, it is likely that riparian losses equal or exceed the loss of the other habitats (Black et al, 2002). While no species extinctions have been recorded as a result of this habitat conversion, the Palouse Grasslands are considered one of the most endangered ecosystems in the United States. Two Palouse Prairie plant communities occurring in Idaho Festuca idahoensis-Symphoricarpos albus (Idaho fescue common snowberry) and Festuca idahoensis, Rosa nutkana (Idaho fescue-Nootka rose) have been proposed for a G1 listing (critically imperiled) (Lichthardt and Moseley, 1997).
At least five animal species of “special concern”, as designated by Idaho Fish and Game (IDFG) and the U. S. Fish and Wildlife Service (USFWS) occur in the grassland habitats of Nez Perce County: northern pygmy owl (Glaucidum gnoma), great grey owl (Strix nebulosa), pygmy nuthatch (Sitta pygmea), ringneck snake (Diadophis punctatus), and mountain quail (Oreortyx pictus) (ICDC, 2003). While all of these species rely on woody vegetation as an essential component of their habitat, mountain quail in particular favor areas with tall, dense shrubs close to water, and are most likely ?declining due to riparian degradation? (DIA, 2003).The Snake River is populated by a variety of fish species, including Snake River chinook salmon (Oncorhynchus tshawytscha), and Snake River steelhead (Oncorhynchus mykis), which are listed as threatened on the federal endangered species list (ICDC, 2003). Little is known about Tammany Creek?s present or historical fishery, but salmonid species have been known to use the lower .25 miles of the stream. A large culvert .25 miles from the mouth prevents fish access to the upper portions of the watershed (NPSWCD, 2002).
Land use in the watershed is varied, with non-irrigated cropland (70%), urban land (21%), grazing lands (8%), and recreational land (1%) (NPSWCD, 2002). At its source, about 3,500 feet above sea level (asl), Tammany Creek is ephemeral and surrounded by rolling croplands. It flows to the northwest for about 5 miles, and then turns west and enters an area with rangelands and suburban development in addition to croplands. In this stretch the creek is intermittent and contained in a concrete channel. Exiting the channel, the creek continues along the southern Lewiston city limits through a mix of agricultural lands and private residences. In this stretch, the creek is fed by groundwater discharge from the shallow basalt aquifer and becomes perennial. Four miles from the mouth the creek enters an area dominated by private residences and grazing land, including several livestock feeding operations. The last mile of the stream is surrounded by mixed agricultural lands, before descending 200 feet through a narrow canyon to join the Snake River at 748 ft asl (IDEQ, 2001).
Historical land use in the Tammany Creek watershed, in addition to the current land uses mentioned, included some mining activity, and dairies (NPSWCD, 2002). A dam was constructed on the creek in the early 1900s to supply water to a large dairy operation. This dam, along with channel straightening, livestock grazing, and land conversion is thought to have contributed to the incised channel in portions of the stream (IDEQ, 2001).
Attempts to address water quality concerns in the watershed have included the Tammany Creek PL566 project, begun in 1985, administered by the Nez Perce Soil and Water Conservation District (NPSWCD). The project?s original focus was on agricultural erosion control, but in 1996 was broadened to include nutrient, pathogen, and temperature issues. The NPSWCD has also used PL566, RCDRP, WQPA, CRP, and HIP program monies to treat streambank erosion (NPSWCD, 2002). PCEI has a successfully completed seven 319 projects in other Columbia Basin watersheds and we are in the process of completing two additional 319 projects.
Tammany Creek is listed on the Idaho 1998 303(d) list as exceeding water quality standards for sediment. Other problems on Tammany Creek include; temperature, fecal coliform bacteria, reduced flow and habitat alteration. The proposed Best Management Practices (BMP) and restoration techniques will reduce sediment loading to Tammany Creek, while filtering runoff from livestock, decreasing temperatures, improving habitat for wildlife and coldwater biota, and stabilizing streambanks. The restoration project will reduce instream channel erosion and associated sediment:
- Reconstructing a narrow low-flow channel
- Resloping and stabilizing streambanks
- Installing coir logs and erosion control fabric
- Planting a variable width buffer of native trees and shrubs between 15 and 30 feet wide
Conditions of concern at Lucky Acres:
- Eroding and unstable bank conditions
- Non-point source loading into Tammany Creek, especially from water flowing across riding arena and horse and livestock stables
- Little to no native vegetation
- Little to no riparian buffer, livestock areas abutting stream
- No filtration buffer between parking and RV areas and stream
Photo Point V6 Upstream (July 2004): Volunteers help pull weeds along a riding arena prior to the beginning of restoration activities.
Pre-Restoration Survey (July 2004): Old swale next to horse washing station before improvements.
Photo Point V5 Downstream (February 2005): Lucky Acres in February, grass starting to poke back up.
Photo Point V1 Downstream (September 2004): Pre-construction
Photo Point V1 Downstream – Installation (October 2004)
Photo Point V1 Downstream (May 2005)
Photo Point V3 Downstream (September 2004): Pre-construction
Photo Point V3 Downstream (October 2004)
Photo Point V3 Downstream (May 2005)
Photo Point V5 Downstream (October 2004)
Photo Point V5 Downstream (September 2004): Pre-construction
Photo Point V5 Downstream May 2005
Photo Point V5 SW September 2004: Pre-construction
Photo Point V5-SW October 2004
Photo Point V5-SW May 2005
Photo Point V6 Upstream (September 2004): Pre-construction
Photo Point V6 Upstream (October 2004)
Photo Point V6 Upstream (May 2005)
Photo Point V6 Downstream (September 2004): Pre-construction
Photo Point V6 Downstream (October 2004)
Photo Point V6 Downstream (May 2005)
Photo Point V8 Downstream (September 2004)Pre-construction
Photo Point V8 Downstream (October 2004)
Photo Point V8 Downstream (May 2005)
Photo Point V9 Upstream (September 2004): Pre-construction
Photo Point V9 Upstream (October 2004)
Photo Point V9 Upstream (May 2005)
Volunteers Plant (November 2004): Volunteers working to plant new vegetation on a sunny November day.
Happy Volunteers: Young community members joined up for a day of work at Lucky Acres.
Pulling the banks back: Tammany Creek along riding arena after the bank has been pulled back.
Swale 4 (November 2004): This new swale just had erosion control fabric installed along the banks for stabilization. The swale mainly collects parking lot run-off for filtration before it can enter the creek.
Swale 4 (November 2004): Here is the same swale after it has been planted with McKenzie willows and seeded with native grass mix.
Lower reach (November 2004): Lower reach after it has just been planted.
Middle reach along riding arena (November 2004): This photo was taken a few weeks after erosion control fabric was installed and native grass seed was planted. The majority of grass seen coming up through fabric is a sterile wheat grass used as a cover crop until the other grasses take root. Note the waddles meandering along the toe of the slope.
Construction Begins (August 2004): Trackhoe opens up a new swale along the riding arena to collect runoff before it reaches the creek.
Grass is sprouting (July 2005): Looking to the west from the upper reaches of the site. You can see the sterile wheat grass has turned brown. This is the last season it will sprout and native grasses will take over.
Thriving grasses and native woody plants (May 2005): An AmeriCorps volunteer stands in the thriving grass. The flagged poles in the foreground mark native species planted by volunteers last fall and this spring.