Long-Term Erosion Monitoring in the Copeland Creek Headwaters

students measure depth to bankephemeral creek monitoring locationtransect measurements

Project Description: Due to the erosive geology in the headwaters of Copeland Creek, the tiny watershed (only 5.1 square miles) produces an astonishing amount of sediment. This project is designed to monitor processes that contribute to sedimentation in the watershed: changes in channel form and creek banks, debris flows, and mud flows. Differences between perennial and ephemeral drainages are explored.

Duration: Spring 2012-present

Type of Educational Activities: service-learning, senior thesis

Project Faculty: Michelle Goman (Geography), Jeff Baldwin (Geography)

Partners: Sonoma County Water Agency, SSU Preserves

Participating Courses:

  • GEOG 360: Geomorphology (Michelle Goman) - 23 students (Fall 2013)
  • GEOG 490: Geography Senior Seminar (Jeff Baldwin) – 1 student (Spring 2012)
sites for erosion monitoring study

Sampling Locations: Monitoring sites are located on Copeland Creek and an unnamed ephemeral tributary and include 5 cross-sectional transects (yellow pins in photo at right), bank erosion pins (co-located on 4 of the cross-sectional transects), Wolman pebble counts (co-located on 4 of the cross-sectional transects), debris flow and mud slide photomonitoring points (green dots), and head scarp erosion pins (white dots).

Methods:

  • Cross-Sectional Transects: Students survey cross-sectional and longitudinal profiles of the creek bed using an autolevel. An arbitrary benchmark of 100 meters is used in all autolevel surveys. Measurements are recorded every 0.5 meters or at sudden slope changes for both the longitudinal and cross-section profiles. A sketch of each site was made using a compass and meter tape.
  • Bank Erosion: Erosion pins (rebar) were set in within the streambank at two locations on the cross-section transects to monitor bank erosion. A measurement of the exposed metal was taken using calipers.
  • Quantification and Characterization of Bed Load Material: Wolman pebble counts were used to characterize grain particle size and distribution of bed and bank material.
  • Head Scarp Movement: Erosion pins (rebar) were placed at the top of two scarps created by debris flows.
  • Debris and Mudflow Movement: Photomonitoring stations were established at the foot of two debris flows and a mud flow.

Field surveys are conducted under the guidance of Michelle Goman and Jeff Baldwin.

Data: (see data disclaimer)

Presentations:

Reports:

  • Stream reach characterization of Copeland Creek, Rohnert Park, California. Alexa Melcon. Fall 2013. (Instructor: Michelle Goman, Geography Department). Class Report. Melcon 2013 (pdf, 0.6 Mb)
  • Fluvial erosion and transport: a study of an ephemeral stream located within the Fairfield Osborn Preserve, Sonoma County, California.. Robbie Gleaton. 2013. (Instructor: Michelle Goman, Geography Department). Class Report. Gleaton 2013 (pdf, 0.8 Mb)
  • Establishing a longitudinal study for sediment input in the Copeland Creek headwaters. Griffin Ballard. 2013. (Advisor: Jeff Baldwin, Geography Department). Senior Thesis. Ballard 2013 (pdf, 2.7 Mb)

Maps:

Reports:

Sediment Analyses in Other Watersheds:

Scientific Literature:

  • Potter, C and S. Hiatt.(2009). Modeling river flows and sediment dynamics for the Laguna de Santa Rosa watershed in Northern California. Journal of Soil and Water Conservation. Vol. 64 (6):383-393.

Data:

  • LiDAR Data: Bare earth projection (4MB); data location
  • Sonoma County Water Agency(data provided by Mark Bautista). The following amounts of sediment were removed from Copeland Creek between 2008 and 2012 to maintain flood capacity in the lower reaches of the channel:
    • 2008 – 5,120 cu yds
    • 2009 – 240+168 cu yds
    • 2010 – 300 cu yds
    • 2011 – 250+760 cu yd
  • Copeland Creek Watershed Assessment (2004) reports the following information on sediment removal:
    • < 1997 – "In the past, flood control channels were cleared at least once every five years."
    • 1997 – “100 percent of Copeland Creek was cleared in 1997"
    • 1998 – “One of the largest sediment removal activities [of SCWA] was performed in a two and half mile stretch of Copeland Creek three years ago (1998).
    • 2000 – “About 2,000 feet of channel was maintained in 2000. Sediment input from a large runoff area upstream has resulted in significant sediment loads into the creek” (R. Anderson, SCWA, pers comm. 2000)
    • 2001 – “Only 17 percent (2,000 ft) requires cleaning this year (2001).”