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