Geomorphology: Applications for Submerged Oil Assessment in the Kalamazoo River, Michigan

1. Geomorphology: Applications for Submerged Oil Assessment in the Kalamazoo River, Michigan Jen Holmstadt, Dave Richardson, Brad Schrotenboer, Pat McGuire, Mike Bigsby, Colin McGuire, Tetra Tech CES Prepared for PIANC Conference, October 24, 2012

2. Overview Crude Oil Spill and Response Introduction to Fluvial Geomorphology Development of Geomorphic Surfaces Geomorphic Approach to Predict Submerged Oil Locations

3. Crude Oil Spill • Crude oil release on July 26, 2010 near Marshall, MI • About 843,000 gallons of crude oil released into Kalamazoo River • Clean-up crews discovered crude oil in river bed sediment (submerged oil) • Geomorphic methods used to assess distribution of submerged oil

4. Geomorphology: Introduction • Geomorphology: Study of landscape formation, evolution, and function. • Consists of several sub-disciplines, including fluvial geomorphology • Fluvial Geomorphology: Science devoted to understanding river systems, in both natural and human-impacted settings

5. Fluvial Geomorphology and Contaminant Spatial Distribution • The spatial distribution of a contaminant is dependent on contaminant characteristics and fluvial processes. • Contaminants associated with the organic matrix of soft sediment (e.g. oil, PCBs) are subject to deposition in low flow areas. • Geomorphic setting and erosion/deposition processes are used to predict soft sediment deposit locations.

6. Multiple Lines of Evidence to Support Geomorphic Interpretation • Multiple variables used to delineate geomorphic surfaces with uniform characteristics • Channel longitudinal profile • Leaf-off aerial photos • Geomorphic fluvial setting • Sediment Type • Channel width • Water depth • Anthropogenic impacts (e.g. dams, erosion control, etc.) • Surfaces used to determine erosional/depositional areas

7. Geomorphic Surface Delineation: Desktop Analysis • Leaf-off aerials allow initial desktop analysis of fluvial system • Provides a geomorphic context for the channel (i.e. floodplain landforms, anthropogenic features, etc.) Small tributary Bridge Backwater

8. Geomorphic Surface Delineation: Banks • Step 1: Delineate banks using large scale (ex: 1:100)

9. Geomorphic Surface Delineation: Gradient • Step 2: Incorporate significant changes in gradient • Used longitudinal profile data

10. Geomorphic Surface Delineation: Fluvial Setting • Step 3: Integrate general changes in fluvial setting • i.e. oxbows, meander bends, islands, cutoff channels, etc.

11. Geomorphic Surface Delineation: Bed Type • Step 4: Edit polygons to reflect general changes in bed type (from poling data) • Sediment type is directly related to depositional/erosional processes

12. Geomorphic Surface Delineation: Water Depth • Step 5: Further refine polygons to reflect changes in water depth (from poling data) • Step 6: Incorporate known anthropogenic impacts • Step 7: Assign geomorphic surface names reflecting depositional/erosional environment ~6.5 ft. Depositional ~4.0 ft. ~5.0 Erosional ~10.0, 7.5, 6.5 ft.

13. Geomorphic Analysis of Submerged Oil • Submerged oil typically most prevalent in depositional areas with soft sediment • Results confirm the relationship between geomorphic surface and submerged oil

14. Summary • Geomorphic interpretation accurately predicted submerged oil depositional areas. • Geomorphic setting, channel width, and gradient have the most influence on submerged oil deposits in the Kalamazoo River. • Geomorphic surfaces can be used to estimate the areas and amount of submerged oil remaining in fluvial system.

15. Questions?

16. Geomorphic Data Collection: Poling • Poling used to measure geomorphic indicators: • Gradient (longitudinal profile) • Water depth • Bed Type • Qualitative method based on sediment agitation used to determine presence and degree of submerged oil Go Badgers!