Timeline

  • Duration: March 2024 - ongoing
  • Partners: City of Redmond, Department of Public Works
  • Status: In-Progress

Overview

The Miller Creek Watershed Mapping project was a six-month collaborative effort to systematically document stream conditions, water quality, and habitat features across the entire 50-mile creek system. This work provides critical baseline data for future restoration planning and climate adaptation strategies.

Methodology

Survey Design

We established 120 permanent monitoring stations at half-mile intervals along the mainstem and major tributaries. Each station was assessed for:

  • Water quality parameters (temperature, pH, dissolved oxygen, conductivity)
  • Physical habitat characteristics (substrate composition, pool-riffle ratios, canopy cover)
  • Biological indicators (macroinvertebrate communities, fish presence)
  • Riparian vegetation structure and composition

Data Collection

Field teams conducted surveys during base flow conditions (July-August) using standardized protocols adapted from EPA's Rapid Bioassessment Protocols. All data were recorded using field tablets with GPS integration for spatial accuracy.

Key Findings

Water Quality

Overall water quality was good to excellent in the upper watershed, with degradation in the lower reaches due to agricultural and urban inputs. Notable findings:

  • Average summer temperature: 14.2°C (upper) to 18.7°C (lower)
  • Dissolved oxygen consistently above 8 mg/L in forested reaches
  • Elevated conductivity in lower watershed (averaging 245 µS/cm)

Habitat Assessment

The watershed retains excellent habitat quality in protected forest lands, but faces challenges in working landscapes:

  • High-quality habitat: 35% of surveyed reaches
  • Moderate quality: 42% of reaches
  • Impaired: 23% of reaches

Biological Communities

Macroinvertebrate assemblages indicated generally healthy conditions, with EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa present in 78% of surveyed sites. Fish surveys documented populations of cutthroat trout, coho salmon, and sculpins in suitable habitats.

Restoration Priorities

Based on our findings, we identified priority areas for restoration:

  1. Upper Tributary Reconnection: Remove three small barriers to restore 8 miles of upstream habitat
  2. Riparian Buffer Enhancement: Establish native vegetation buffers along 12 miles of agricultural reaches
  3. Thermal Refuge Creation: Enhance groundwater-fed side channels for summer refugia

Data Accessibility

All survey data and spatial datasets are publicly available through the County GIS portal. Interactive maps allow community members to explore conditions throughout the watershed.

Next Steps

This baseline assessment sets the stage for ongoing monitoring and adaptive management. Annual follow-up surveys will track changes over time and help evaluate restoration effectiveness.

Project Team: Sarah Chen (Project Lead), Miguel Torres (Field Coordinator), 42 Community Volunteers

Funding: State Water Quality Grant, County Conservation District, Private Foundations