mofep annual meeting 11/30/2004 evaluating timber harvesting effects on water quality in low-order...
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MOFEP Annual Meeting11/30/2004
Evaluating Timber Harvesting Effects on Water Quality in Low-Order Streams in the Missouri Ozarks
John Bowders, David Hammer,
Ryan Mueller, Craig Bunger, Abe Smith
Civil & Environmental Engineering
University of Missouri-Columbia
MOFEP Annual Meeting11/30/2004
Collaborating Entities
Missouri Department of Conservation (MDC)
Missouri Department of Natural Resources (MDNR)
Institute for Interdisciplinary Geotechnics (I2G)
Civil and Environmental Engineering
MOFEP Annual Meeting11/30/2004
Problem Statement
MOFEP Annual Meeting11/30/2004
Objectives
Determine if measurable and significant impacts exist
Evaluate equipment and refine sample collection methodology
Evaluate BMPs
MOFEP Annual Meeting11/30/2004
Study Location
Angeline & Current River Conservation Areas
Current River Hills and Breaks LTAs
MOFEP Annual Meeting11/30/2004
Project Design
2 to 3 years of pre-harvest
background data
Complete timber harvest and
slashing (ROCC prescription)
3 years of post-harvest data
10 harvest sites, 5 control sites
4 sites intensively monitored
11 site extensively monitoredNigh, 2000
MOFEP Annual Meeting11/30/2004
Typical Ephemeral Channel
MOFEP Annual Meeting11/30/2004
Intensively Monitored Sites
4 sites, close geographic proximity
ISCO® automated sampling devices
Hand-built equipment for verification
MOFEP Annual Meeting11/30/2004
Extensively Monitored Sites
11 sites, discretely distributed
Hand-built instrumentation
Gather “coarse data” for comparison with intensively monitored sites
MOFEP Annual Meeting11/30/2004
Sediment Trap
Sediment Trap Catchment
Sediment Filter ConeSediment Trap
MOFEP Annual Meeting11/30/2004
Rising Gauge Water Sampler
Sample Collection Bottles Inlet Ports
MOFEP Annual Meeting11/30/2004
Additional Instrumentation
Stream crest gauges
Rain gauges
Silt Fencing
MOFEP Annual Meeting11/30/2004
Typical Equipment Layout
Site boundary
Harvest boundary
Sediment trap
In-stream sampler(bottle sampler/ISCO)
Ephemeral Stream
Extensively Monitored Study Site
MOFEP Annual Meeting11/30/2004
Site Characterization
LTA: Current River Breaks
Avg. basin area: 50 acres
Stream Order: 2nd and 3rd
Avg. relief: 280 ft.
Drainage density: 0.01 m-1
Predominant slope range:
20 – 30 percent
MOFEP Annual Meeting11/30/2004
Ground Cover Estimate
MOFEP Annual Meeting11/30/2004
Analytical Testing
Sediment: Total Suspended Solids
Nitrogen: NH4+, NO3-, Total Nitrogen
Cations: Ca2+, Mg2+
Nutrients: K, P
pH, Conductivity
MOFEP Annual Meeting11/30/2004
BenefitsEvaluation of cause-and-
effect relationships of timber harvesting on water quality for low-order watersheds
Provide data to meet public expectations of sustainable quality and environmental stewardship
Determine if modification of BMPs is necessary
MOFEP Annual Meeting11/30/2004
Key Findings
Threshold precipitation event ~ 2 inches
Discrete Recharge (karst) Features can ‘swallow’ the entire channel flow
Baseline sediment (from traps) almost non-existent
Cut-banks appear to be responsible for sediment
MOFEP Annual Meeting11/30/2004
Challenges
Effectively instrumenting the sites
Response time & sample collection frequency
Setting detection limits for water analyses
Harvest period disruption
Frequency of threshold level precipitation events
MOFEP Annual Meeting11/30/2004
Developing Research IssuesApplicable Water Quality
Standards
Discrete Recharge (karst) Features (DRF)
Aley 1978
MOFEP Annual Meeting11/30/2004
MOFEP Annual Meeting11/30/2004