LEWIS

1
LEWIS CLARK LAKE WATERSHED ASSESSMENT

• Randall Resource Conservation Development
  Association Inc.
• And
• South Dakota Department of Environment Natural
  Resources

2
Ft. Randall Dam Pickstown, SD
3
Protecting a National Resource

• Starting in 1930s with the first dam, six dams
  on the Missouri River now provide
• Quality drinking water
• Water for irrigation
• Hydropower
• Flood control
• Recreation
• Fish and Wildlife habitat
• Endangered Species and Cultural Resource
  Protection

4
Lewis and Clark Lake WatershedSouth Dakota
Nebraska2 million acres in SD 8 million in NE
5
Problem Identification

• Randall RCD has a long history of working with
  Missouri River Issues. Most assistance included
  on-site projects on riverbanks and surrounding
  land affected by the river
• High flows in 1993, 95, 97 caused bank erosion
  problems up and down the Missouri river
• A new problem came to forefront. A massive
  sediment delta has and continues to displace open
  water in the Lewis and Clark Lake
• The six dams on the Missouri River were designed
  with a Design Life concept like most
  engineering practices instead of a Life Cycle
  Sustainable Use Approach

6
Lewis and Clark Lakes Lifespan was estimated from
75 to 135 years
7
(No Transcript)
8
Re-action vs. Action

• What is being done to manage the health, the
  harmful
• effects of sediment and prolong the life of the
  dams?
• Elevation of roads in danger or flooding
• Moving drinking water intakes that are clogged or
  in shallow water and non-functioning
• Establish new boat launch pads
• Government buy-out of homes costing millions and
  only treating symptoms, not dealing with sediment.

9
Background

• Local Organizations were concerned about the
  sediment delta buildup in Lewis and Clark Lake.

10
Request for Assistance

• 1998 Charles Mix County Commissioners submitted a
  request for technical assistance to Randall RCD
• 1999 Jan-Mar public meetings held with landowners
  and agencies
• 2000 Randall RCD teamed up with neighboring
  RCDs and held 5 summits with an EPA 319 grant
• 2000 SD legislature established a Missouri River
  Trust Fund with an aim of 200 million dollars for
  future river health issues
• 2003 Conservation Districts in SD and Natural
  Resource District in NE met with 5 RCD/s from NE
  and SD. All agree a watershed assessment was
  needed
• Randall RCD agreed to take the lead with help
  from the Lower James RCD in SD

11
Locating treating sediment sources
Partners
SD DENR
Randall RCD
City, State, Federal Govt. Conservation
districts Etc,
Technical guidance
Organization fundraising
Lewis Clark WS Assessment
Objective Locate sources of sediment so they
can be treated
12
Funding

• EPA sec. 106 CWA
• EPA 604B CWA
• SD DENR
• Local cash match
• 5 RCDs
• 9 SD CD
• 4 NE Nat. Res. Dist.
• 2 rural water org.
• 1 watershed district
• 1 water dev. District
• 2 SD towns

• 273,500
• 80,000
• 8500
• 37,600
• 399,600 total

13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
Room for improvement
20
Emanuel Creek Photos taken upstream and
downstream from the same bridge
Upstream
Great riparian protection stream is stable
Downstream
Heavy grazing impact leading to incision and
erosion
21
OUR APPROACH
Assess major tributary streams
Analyze the landscape
Utilizing a computer program to assess the
erosion potential of large pieces of land
Compare sediment input from different streams
22
Computer assistance is crucial

• Ten million acres in the LC watershed
• 24 months to complete an assessment

Annualized AGNPS Model increases efficiency
Processor
AnnAGNPS Model
23
AnnAGNPS Modeling Results
104 tributaries have been modeled
Soil Loss tons/acre
24
RGA - Rapid Geomorphic Assess.
Upstream
Photos from the same road crossing!
Downstream
Incision, bank stability, accretion, riparian
vegetation, constriction
25
Tributary Sampling
26
Suspended Solid Loadings
Keya Paha River
Ponca Creek
Choteau Creek
Emanuel Creek
Niobrara River
Verdigre Creek
27
DIRECTION OF PROJECT
24 months of analysis completed
Analysis completion date is January 2007
Our findings will be used to direct erosion
control policies (and funds) throughout the
watershed.
28
Assessment as of 2006

• Critical areas identified prioritized.
• Development of one sub watershed
• Implementation Plan with
• Established Goals, Objectives and Strategies.
• Selected Implementation Practices.
• Financial Assistance of 319 s and existing
  sources (NRCS, FSA Others).
• Technical Assistance with Project Coordinator
  hired through the Randall RCD.

29
Questions?
Ft. Randall Dam Pickstown, SD