Fifteenmile Creek

Since the 1990s, landowners in the Fifteenmile Creek watershed have been working with their local Watershed Council, Soil and Water Conservation District, and other partners to to reduce soil erosion, build healthier soils, and monitor water quality. This “whole watershed” restoration approach recognizes that improvements in farm efficiencies are a win-win, contributing to healthy streamside vegetation and maintaining high water quality and healthy fish habitat.

Fifteenmile Creek flows into the Columbia River just downstream of The Dalles Dam. The watershed is in the rain shadow of the Cascade Range, with rainfall averages of 27 inches in the west and 12 inches in the east. It is home to a variety of fish species, including wild steelhead, Pacific lamprey, resident redband trout, and coastal cutthroat trout. It’s also occasionally used by spring Chinook and coho salmon. About 72 percent of the watershed is used for agriculture, primarily dryland wheat.

To understand the water quality problem in the Fifteenmile Creek Watershed, it’s important to look back at previous decades of land use in the area following World War II. During the post-World War II economic boom, farmers needed to quickly break new ground to develop cropland, often using new technology to rise to the challenge. At that same time, typical land uses on national forests in the area included timber harvesting and livestock grazing. Road construction and public road use was on the rise, as the demand for timber increased along with the need for housing and escalating national interest in outdoor recreation. Decades of intensive land use disturbed soils, which contributed sediment to streams. Too much sediment in waterways degrades salmon spawning areas and interferes with juvenile fish development and feeding. Over the years, agricultural and forest practices impaired vegetation growing alongside streams, reducing the number of trees and shrubs. Trees and shrubs help stabilize stream banks, filter runoff and provide shade that cools water temperatures. The combination of all these factors slowly degraded water quality over the years. In 1998, the Oregon Department of Environmental Quality (DEQ) included the streams in this watershed on the Clean Water Act Section 303(d) list of impaired waterways for both sediment and temperature. That decision motivated government and private landowners to come together to restore and protect this vital water system. Listing the watershed raised public awareness and provided strong rationale for restoration funding. Additionally, back-to-back 100- year flood events in 1995 and 1996 got landowners’ attention and set the stage for change.

Agencies at the local, state, and federal level worked with private landowners and nonprofit organizations on several restoration actions to improve water quality and stream habitat:

• Establishing and Protecting Streamside Vegetative Buffers
• Converting to Direct Seeding/ No-Till Practices
• Improvements to Forest Management Practices
• Temperature Stabilization

Since the late 1980’s, landowners established vegetative buffers along 90 percent of the perennial stream miles on privately-owned land within the watershed. This work was funded by multiple agencies, including the Bonneville Power Administration, the Oregon Department of Fish and Wildlife (ODFW), the Oregon Watershed Enhancement Board (OWEB) and others. These streamside vegetative areas have rebounded to provide shade, water quality functions, and other benefits to protect the water and keep it healthy. Additionally, a majority of the perennial streams in the Fifteenmile Creek Watershed have streamside vegetative buffers enrolled in the Farm Service Agency’s Conservation Reserve Enhancement Program (CREP). This voluntary program restores and protects land along streams and other water bodies by targeting high-priority conservation areas identified by local, state, or tribal governments or non-governmental organizations. In exchange for removing environmentally sensitive land from production and introducing conservation practices, farmers and ranchers are paid an annual rental rate. Wasco County Soil and Water Conservation District (SWCD) field surveys show that, five years after planting, vegetation buffers help maintain streamside habitats.

By working directly with farmers, the Natural Resources Conservation Service (NRCS) and other partners have been helping growers transition from traditional plowing to direct seeding practices. This reduces soil disturbance, creating habitat that allows soil microbes and insects to thrive. Direct seeding practices increase water infiltration, boost soil organic matter, reduce erosion, and improve nutrient cycling for plants. Now, almost 100 percent of the agricultural lands in Fifteenmile Watershed are farmed using direct seeding practices. A variety of funding sources helped growers make the transition from older methods. Those included grant programs from Oregon DEQ, the Oregon Watershed Enhancement Board (OWEB), and the NRCS.

Solutions also came to fruition on federally-owned United States Forest Service lands within the watershed. With increased funding for conservation over the past several decades, the Mt. Hood National Forest conducted several restoration projects in the Fifteenmile Creek Watershed, such as:

• Decommissioning heavily-eroded roads near streams
• Improving fish passage
• Stop fish from getting trapped in water transportation systems
• Re-vegetation and reforestation of degraded areas
• Protecting and improving riparian vegetation; and
• Treating densely forested timber stands to reduce the risk of severe wildfire.
• The changing culture of natural resource management demands landscape-scale restorations—working with other agencies and partners—to minimize impacts to aquatic habitats, soil and water quality. This whole watershed approach, spanning public and private lands, continues today— not just in the Fifteenmile Creek Watershed, but in many streams throughout Oregon, the Pacific Northwest, and the nation. 

In 2019, the Oregon DEQ produced a report evaluating changes in sediment and biological conditions in Fifteenmile Creek by comparing data collected in recent years (2015 and 2016) with data collected earlier (1994 and 2000). Six out of seven stations with data available for comparison showed improved sediment quality, as measured with a decrease in the percent fine sediment. Three of these stations were adjacent to agricultural land. Eleven out of 14 samples collected in recent years met the ODFW recommended benchmark for sediment, and six of these were adjacent to agricultural land. It is important to continue evaluating sediment condition using consistent methods so that results can be compared over time to evaluate how the watershed responds to agricultural implementation practices. Biological studies, such as looking at the freshwater macroinvertebrate community, can provide a relevant and cost-effective way to evaluate habitat condition.

Farmers and practitioners with a long history of working in Fifteenmile continue to see less erosion from fields that are using direct seed/no-till practices. Communication among landowners and with land managers continues to improve, and partners are sharing lessons learned to plan future restoration and irrigation efficiency projects. Using these observations, as well as the results of recent reports, local, state and federal partners can design future studies to look at water quality, macroinvertebrate community and fish habitat response to land management and natural events such as floods and fires. Throughout the Fifteenmile watershed, landowners and partners are committed to tackling tough new problems as they are identified. 

Taking a whole watershed approach requires collaboration, partnerships and leveraged funding among local, state and federal agencies and conservation groups. Each partner contributed technical and financial assistance to efficiently use conservation dollars while concentrating efforts in priority areas in the watershed. Partners for this project include: 

• Private landowners
• Fifteenmile Watershed Council
• Wasco County Soil & Water Conservation District
• Bonneville Power Administration
• The Freshwater Trust
• Oregon Department of Agriculture
• Oregon Department of Environmental Quality
• Oregon Department of Fish and Wildlife
• Oregon Water Resources Department
• Oregon Watershed Enhancement Board
• USDA Natural Resources Conservation Service
• USDA Farm Service Agency
• USDA Mt. Hood National Forest

Oregon's Conservation Effectiveness Partnership seeks to describe the effectiveness of cumulative conservation and restoration actions in achieving natural resource outcomes through collaborative monitoring, evaluation and reporting.