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UTAH
Utah's nonpoint source program owes its success to the cooperation among
local, state, and federal agencies. This cooperation enables Utah to better
achieve its major goal of reducing human-induced nonpoint source pollution. The
Murray-Jordan River Parkway demonstration project, located in the Salt Lake
City metropolitan area, is an excellent example of cooperation in action.
Streambank Modification Successful in Utah
Improving water quality by reducing pollutants--metals, sediments, and
nutrients--was the goal when Murray City began a demonstration project in March
1990 to restore the Jordan River streambanks.
The aim of the streambank demonstration project was to install streambank
modification best management practices to improve the slope, install riprap to
protect against seasonal high flow, revegetate the slopes with native species
(including grasses, shrubs, and trees), and construct two wetland pond systems
to treat urban runoff before discharging to the Jordan River. These BMPs were
designed in consultation with EPA, Corps of Engineers, Utah State Engineer,
Parks and Wildlife Resources, Murray City, and Salt Lake County. Section 319(h)
grant funds, in coordination with the Utah Departments of Environmental Quality
and Agriculture, contributed about $60,000 of the $150,000 cost. Murray City
contributed the rest.
The project was organized into two phases. Phase I, completed in May 1991,
centered on the entire length of the west banks; Phase II, completed in August
1992, focused on the eastern banks. The project began with regrading the bank
to a 3 to 1 slope. Then workers planted nearby cottonwood saplings, - followed
by grasses, shrubs, and other trees. Murray City installed a sprinkler
irrigation system to help seed germination. A second wetland pond system was
completed in early spring 1992 to complement the first system, in operation
about three years.
Excavated material from grading was used to construct trailside berms
throughout the city, and broken concrete from steepened banks was buried or
hauled to landfill sites. Large angular boulders from a local quarry were used
on the finished bank slope and filled in with smaller material. Riprap was not
used continuously along the segment. Vegetation such as willows or other native
species were planted in open slope areas. Minor modifications were made where
the stream course changed slightly.
Cottonwoods were transplanted early, followed by birch, box elder, willow,
dogwood, sumac, wood rose, currant, and other donated species. Larger species
were grouped on upper slopes, and shrubs and willows were grouped on - middle
and lower banks. Much of the planting was done during Earth Day activities
sponsored by Murray City by over 1,000 community volunteers. After broadcast
seeding of a native grass mixture in mid-May, liquid mulch was applied. Dry
weather caused some grass species to fail. Later in the season, several of the
dominant species took over, such as clover, wheat grass, alkali sacaton, Great
Basin wild rye, and reed canary grass. Wildflower carpets of 1,000 square feet,
providing 15 species of draught tolerant wildflowers, were grown in an
artificial root-holding mat similar to regular grass sod.
The BMP successes are easy to see. The grading and installation of riprap
facilitated the irrigation of the native and ornamental plant species that now
flourish on both east and west river segments. Stormwater additions to the
oxbow and constructed wetland ponds are beginning to net large growths of water
dependant plants--Typhales, Scriptus, Carex, Juncus, and Phragmites. The
wetland complexes are growing rapidly and will increase water quality
management performance. Most understory and overstory plant species have
survived and are reproducing.
Salt Lake County data, collected in 1990 and 1991 at the demonstration
project site, showed some water quality improvement. Results of sampling at
upstream and downstream stations showed decreasing concentration of - arsenic,
zinc, total suspended sediment, dissolved oxygen, nitrate, and phosphorus,
except during runoff periods. During high flows from storm activity,
concentrations were greater at the downstream site, probably because of the
stormwater discharge located between the two sites. In September 1992, the
project was the site of the first "Celebration of Clean Water" sponsored by the
Utah Department of Environmental Quality, Department of Natural Resources, and
other local agencies.
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