Introduction

Hood River drains 339 mi² on the northern side of Mt. Hood in Oregon and joins the Columbia River at the city of Hood River (fig. 1). Annual precipitation varies with topography, exceeding 110 in. in the southern, high elevation areas near Mt. Hood and averaging 30 in. on the valley floor near the city of Hood River. Most of the Hood River basin is forested and much of the remaining land is in agriculture (appendix A). Hood River is the largest city in the basin and has a population of 6,945 (U.S. Census Bureau, 2010). Agriculture, forest products, and tourism provide the economic base of the area.

Historically, the Hood River and its tributaries served as important spawning and rearing streams for anadromous and nonmigratory salmonids and for Pacific lamprey. Currently, three salmonids native to the Hood River basin are listed as “threatened” by the U.S. Fish and Wildlife Service (2010) under the U.S. Endangered Species Act—bull trout, steelhead, and Chinook salmon—in response to declining populations. The Pacific lamprey is a culturally significant fish for the native tribes along the Columbia River. As recently as 1963, Pacific lamprey were found throughout the basin (U.S. Department of Agriculture Forest Service, 1996). Their population has been limited to the lower 4.5 miles of Hood River since at least the mid-1990s. Three hundred seventy-three miles of streams in the Hood River basin are classified as critical habitat for salmonids (StreamNet, 2010). Instream passage barriers, flow modification, impaired water quality, and natural and anthropogenically induced sedimentation have been identified as contributors to the declining populations (Coccoli, 2004).

To begin to address impaired water quality related to agricultural activities, the Oregon Department of Environmental Quality (ODEQ) initiated a pesticide stewardship partnership (PSP) in the Hood River basin in 1999. Working in conjunction with growers, agricultural extension agents, the soil and water conservation district, watershed council, the Confederated Tribes of Warm Springs, and Oregon Department of Agriculture, the PSP seeks to “identify problems and improve water quality associated with pesticide use at the local level” (Oregon Department of Agriculture and others, 2008). Water was collected from streams throughout the Hood River basin and was analyzed for nine currently used pesticides. The organophosphate insecticides azinphos-methyl and chlorpyrifos were frequently detected in streams that flow through agricultural land at concentrations that periodically exceeded Oregon’s acute or chronic water-quality standards (Coccoli, 2004). Monitoring has continued during the last decade as growers have implemented best management practices to try to minimize the offsite movement of pesticides and to reduce negative impacts to nontarget organisms.

First posted June 17, 2011