South Platte River Program Notes
by Ben Urbonas, P.E., Chief, South Platte River Program
The South Platte River Program continues to work with the cities, counties, special
districts and property owners along the river to help preserve its corridor, improve
conditions and habitat of the river, and assist with the maintenance of this valuable
natural resource downstream of Chatfield Reservoir. One of the largest open space
preservation activities this year was the acquisition, by Adams County, of the Bromley
property. We were proud to assist this effort and contributed a significant portion of the
total funding. This effort will now insure that approximately 140 acres of land will be
preserved and reclaimed for wildlife and human enjoyment as a natural area along the
river.
Maintenance Activities
Routine Maintenance
In 2002, South Platte River routine maintenance efforts included:
- 192 river miles (equivalent) of trash and debris pickup and removal
- 3.6 acres of string-trim mowing at access ramps and rest areas
- 78 miles (equivalent) of recreation/maintenance trail edge mowing
Due to this year's drought conditions, the projected need for 9.1 miles of tree
trimming and pruning along the river trails was unnecessary.
Approximately 180 truckloads of trash and debris were removed from the river and taken
to landfills. Next year we will be adding a total of 5.3 miles of trash and debris pickup
to our routine maintenance activities. The ultimate goal will be to include the entire
reach of the river from Chatfield Reservoir to 168th Avenue. Colorado Total Maintenance,
Inc. has been selected to perform these services in 2003.
For the sixth consecutive year we participated in the Greenway Foundation's annual
NIMBY (Not In My Back Yard) Fest volunteer trash pickup, during which an additional 60
cubic yards of trash were removed. In addition, government personnel and volunteer groups
have picked-up and removed trash from the river corridor throughout the year. Trash is
also regularly removed from trash receptacles that are maintained by park personnel along
all recreational trails.
Not only does our routine contractor remove lightweight debris, but also many heavier
items such as 200 cubic yards of reinforced concrete pipe, heavy equipment tires and scrap
metal. This effort has not only made the river more scenic but has also improved safety
for recreational users.
Routine maintenance continues to be the most cost effective program in terms of
environmental enhancement and public service. Without it, the trash along and in the river
would accumulate tremendously. The routine maintenance program now completes more than
twice the number of trash pickups and trail mowings along the South Platte River than we
did 15 years ago.
Noxious Weed Management
In 2002 the Routine Maintenance Program continued to work with local government
agencies to control infestations of non-native and undesirable tree species along the
river. In the City of Brighton's Morgan Smith nature area we removed approximately 50
Russian Olive trees and planted 80 Cottonwood trees and Peach Leaf Willows. Working with
the South Suburban Park and Recreation District and the City of Littleton, we removed 180
Russian Olives from the riverbanks in South Platte Park. In addition, we removed over 50
dead Siberian Elms in Denver County. Most of the trees that are removed, with the
exception of Russian Olive, are mulched and placed back on the banks to protect soils from
erosion.
The removal of invasive non-native trees provides the opportunity for native
cottonwoods, box elders, willows, and others to be planted or to establish naturally on
their own. These native species provide the best habitat for the indigenous wildlife along
the river.
An area of growing concern is Invasive Noxious Weeds. These weeds threaten habitat,
decrease the value of infested lands to the indigenous wildlife and adversely affects
public use. With the adoption of an integrated approach to noxious weed management, the
routine maintenance program is now equipped to deal with invasive weed species. Our
efforts include aggressive weed mowing, hand pulling and selective use of approved
herbicides. Our relationship with various county weed managers allows us to coordinate
everyone's activities to maximize public benefit of these efforts.
For the second year in a row, District personnel have attended the Colorado Weed
Management Association's (CWMA) yearly conference. This forum provides training in Noxious
Weed management and control and an opportunity to network with experts in this field.
District personnel also attend monthly CWMA meetings sponsored by the Colorado Division
of Wildlife. The relationships that have developed from these meetings are helping us to
continue to be an effective partner in the fight to control noxious and invasive plant
species.
Restoration Maintenance
In 2002, the restoration maintenance program did the following projects:
- Constructed a new boulder grade control structure at the Henderson flow gage near 123rd
Avenue in Adams County (See "Rebuilding Henderson Gage
Control Section")
- Reconstructed of the Gardener's Diversion Dam just upstream of the York Street bridge in
Adams County
The reconstruction of the Gardener's Diversion Dam was a cooperative design and
construction effort between the District and Xcel Energy. An old, failing, wooden
diversion structure, operating as a makeshift river grade control, was removed and
replaced with a sloping, partially grouted boulder grade control structure. For safety and
fish passage reasons, a boatable chute (assuming we have adequate water flow) was
incorporated into the structure. Xcel split the cost of the grade control and designed and
paid for a concrete water diversion/bypass structure in order to supply water to the
Cherokee Power Generating Plant.
The District continued to assist local governments with maintaining the recreation
trail used by the District for maintenance access.
In 2003 we expect the program to include the following restorative maintenance
projects:
- Construction of sloping boulder grade control structure and bank restoration upstream of
120th Avenue in Commerce City
- Extension of the river recreation trail northward below 104th Avenue (also funded by
Adams County)
- Construction of boulder grade control structure and old bridge pier removal at 16th
Street in Denver
- Several bank stabilization and restoration projects in Adams County, Thornton, and
Littleton
- Design and construction funding assistance for pedestrian trail crossing in Adams County
Cooperative Projects with Private Property Owners
Cooperative projects are constructed on flowage and maintenance access easements
dedicated to the District by private property owners adjacent to the river in exchange for
river restoration work. To date over 630 acres of such easements have been dedicated,
resulting in over 24 bank stabilization and/or river grade controls and riparian
revegetation projects since 1988. In most cases, the local parks departments use these
easements for the construction of recreation trails which double as river maintenance
access.
No new cooperative projects were constructed this year, however, two more easement
dedications were completed. The previously mentioned Bromley property, purchased by Adams
County, included a flowage and drainage easement that now allows the District to perform
river maintenance and have a voice in how this property will develop. The McIntosh Farm
Company also dedicated 31 acres of riparian area in order to get District assistance with
bank stabilization and restoration along their property. We hope to complete this bank
work in 2003.
Capital Improvement Projects
Upper Central Platte Valley Project
The U.S. Army Corps of Engineers has now completed the river reclamation improvements
for the Colfax Reach (I-25 to 14th Avenue) of the river in Denver. The Corps has also
completed a Feasibility Study of a river restoration project for the Sun Valley and Zuni
Reaches (14th Avenue to upstream of 8th Avenue) in Denver. Final design is underway by the
Corps for this $18,000,000 project; however, Congress has not yet authorized construction
funds.
Phase 3 of Globeville Project
The District has been working with the City and County of Denver to develop a new
design for Phase 3 of the Globeville project along the South Platte River. This phase will
relocate the diversion dam for Burlington Ditch upstream of Franklin Street and, in the
process, take over 200 acres of residential, commercial and industrial lands out of the
FEMA designated 100-year floodplain in Denver. Because of the unusual geometries involved,
the entire diversion system and channel modifications are being studied at the Colorado
State University Foothills Hydraulics Laboratory in Fort Collins. Denver and the District
hope to have this project sufficiently advanced to begin construction in late 2003.
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