w.
h.'^^^^^^^J
         \
              Section 319
              NONPOINT SOURCE  PROGRAM SUCCESS STORY
 Forestry, Agricultural, and Stormwater Best Management Practices

 Improve Quality of Reservoir

Waterbodv Imoroved  Water Quality in the Cascade Reservoir, 70 miles north of
                             Boise in central Idaho, has been adversely affected by
 phosphorus loading from various sources, including forestry operations and agricultural
 activities. By upgrading forest  roads  and implementing grazing best management practices,
 project partners saw a 57 percent  reduction in phosphorus, exceeding the 37 percent
 reduction goal.

 Problem
 The Cascade Reservoir has been plagued with
 excessive algae blooms that have degraded
 fish habitat and caused poor water quality
 for swimming and boating. Water quality
 studies identified phosphorus as the pollutant
 of concern in the watershed, and as a result
 the reservoir was added to the state's 303(d)
 list for phosphorus. Point source pollution
 from wastewater treatment plants and a fish
 hatchery contributed about 10 percent of the
 phosphorus loading to the watershed. Nonpoint
 sources like forestry, agriculture, and  urban
 areas contributed an estimated 84 percent,
 and poorly functioning or failing septic tanks
 were the source of the remaining 6 percent.
 The Cascade Reservoir Phase II Watershed
 Management Plan outlined a need to  reduce
 phosphorus by 37 percent throughout
 the watershed to bring the reservoir into
 compliance with water quality standards.


 Project Highlights
 In 1995 the Idaho Department of Environmental
 Quality initiated a phased total maximum daily
 load (TMDL) process to address concerns
 about excess phosphorus. Forestry implemen-
 tation projects addressed road-related sedi-
 ment runoff along more than 109 miles of  road
                                         Before: Drain ditch leading
                                         to Cascade Reservoir prior
                                         to installation of BMPs.
                                             After: Drain ditch after
                                          cattle have been removed
                                            from the ditch area and
                                           vegetation reestablished.
                                         by graveling 81 miles, closing 3.5 miles, paving
                                         0.1 mile, and installing drainage upgrades on
                                         24.7 miles of road. Agricultural implementa-
                                         tion projects addressed grazing and irrigation
                                         management through livestock exclusion,
                                         fencing, tree and shrub planting, and wildlife
                                         habitat management. Urban and suburban
                                         implementation projects included the creation
                                         of wetlands as indirect treatment measures
                                         for stormwater discharges, as well as imple-
                                         menting parking lot upgrades and drainage
                                         improvements as  direct stormwater treatment
                                         measures.

-------
            Summary of Estimated Phosphorus Loads and Reductions for Point and Nonpoint
            Sources in the Cascade Reservoir Watershed, 1994 through 2002

Point Sources
McCall Wastewater Treatment Plantb
Idaho Fish and Game fish hatchery
Point source totals
Nonpoint Sources
Forestry
Agriculture
Urban and suburban
Septic systems
Unidentified and natural sources
Nonpoint source totals
Grand Total
Total Load
(kg/yr)
3,947
726
4,673
8,840
11,740
4,423
2,205
8,508
35,716
39,881
Projected Reduction
(kg/yr)a
3,947
508
4,455
2,652
3,485
1,359
1,544
2,134
11,174
15,121
Reduction Achieved
to Date (kg)
3,947
508
4,455
2,675
745
255
838C
80
4,593
8,540
Percent of Reduction
Achieved to Date
100%
100%
100%
101%
21%
19%
38%
4%
41%
57%
             a Contains management, natural, and background loading.
             b Construction of winter storage pond is not yet complete. Storage and delivery systems will be completed and tested.
              Additional options for effluent use are being investigated to ensure that the system will operate with no discharge to North
              Fork Payette River in extreme water years.
             c The 838 kg figure used assumes that all septic-to-sewer hookups completed included proper decommissioning of the septic
              tanks. This assumption has yet to be validated. Septic decommissioning is being evaluated.
            Results
            Initial monitoring data indicate a 57 percent
            reduction in phosphorus, exceeding the 37 per-
            cent reduction goal. The reductions achieved
            have resulted in improved water quality condi-
            tions in the reservoir. Improved dissolved oxy-
            gen conditions were observed in the reservoir
            in 1999, 2000, and 2001. Continued reductions
            in phosphorus from  nonpoint sources are
            expected through the participation of partners
            throughout the watershed.
Partners and Funding
This project's success has been ensured
through the broad participation of agencies and
the local project sponsors. Partners include the
Idaho Department of Lands, USDA's Natural
Resources Conservation Service and Forest
Service, Boise Cascade Corporation, Valley
Soil and Water Conservation District, City of
McCalls, and local residents. Project costs from
1997 to 2004 totaled more than $20 million.
Section 319 grants accounted for approximately
$1.05 million in project funds and were used to
implement best management practices, includ-
ing forest road upgrades, grazing management
activities, and stormwater treatment wetlands.
I
5
Q
'.    U.S. Environmental Protection Agency
 \   Office of Water
 a   Washington, DC

     EPA841-F-05-004C
     July 2005
For additional information contact:
Todd Maguire
Nonpoint Source Management Program
Idaho Department of Environmental Quality
208-373-0115  •  todd.maguire@deq.idaho.gov

-------