Black River Hydrologic Analysis

An official website of the United States government

Here's how you know

Official websites use .mil

A .mil website belongs to an official U.S. Department of Defense organization in the United States.

Secure .mil websites use HTTPS

A lock () or https:// means you’ve safely connected to the .mil website. Share sensitive information only on official, secure websites.

US Army Corps of Engineers

Little Rock District Website

/ / /

Black River Study

Home

Little Rock Home

Study Overview

Location: Butler County, Missouri - Black River Watershed

Purpose: Evaluate flooding issues and potential mitigation strategies along the Black River

Study Area: From Clearwater Dam to Corning, Arkansas (approximately 200 miles)

Key Findings

Primary Cause: Recent flooding is primarily due to increased precipitation patterns
Precipitation Trends: Statistically significant increases in annual totals, storm intensity, and frequency of high-intensity events
Streamflow Changes: Significant increases in baseflow and runoff components
Groundwater Impact: High connectivity between groundwater and surface water prolongs flooding conditions
Channel Stability: No major bed changes from 1948-2019, indicating flooding increases are precipitation-driven

Analysis Components

The comprehensive study included:

Clearwater Dam operational scenario analysis
Geomorphic mapping and channel analysis
Precipitation and streamflow trend analysis
Groundwater-surface water interaction modeling (GSSHA)
Surface water hydraulic analysis (HEC-RAS)

Implementation Options & Recommendations

1. Standard Channel Maintenance with Low Water Weir

Partial channel cleanout from Hargrove Pivot Bridge to state line with flow control at Swift Ditch

RECOMMENDED

Benefits:

Reduces water surface elevations by approximately 0.5 feet
Allows river to naturally scour and maintain capacity
Addresses safety concerns from debris
Sustainable with regular maintenance

Implementation: Standard maintenance approach equivalent to 1990s USACE clearing project

2. Two-Stage Ditches and Local Drainage Improvements

Improve local drainage systems with enhanced ditch designs and potential tile drains

RECOMMENDED

Benefits:

Significant impact on reducing groundwater flooding issues
More targeted approach to agricultural drainage
Reduces groundwater surface elevations by ~0.5 meters
Best management practice for areas with perennial flow

Application: Most effective where ditches require frequent maintenance due to sediment deposition

3. Levee Setbacks

Relocate levees away from river channel to provide additional floodplain

RECOMMENDED

Benefits:

Greatest water surface elevation reduction (2-6 feet)
Reduces pressure and failure risk on levees
Significantly reduces flood duration (weeks to days)
Provides space for natural river processes

Considerations: Generally unpopular with landowners due to land acquisition requirements

4. Transverse Levee Removal

Remove short levees at Coon Island Conservation Area

LIMITED BENEFIT

Impact:

Very localized water surface reduction (up to 1 foot)
Benefits limited to 4,000-5,000 cfs flow range
Minimal impact on flood duration

Assessment: Local drainage improvements would provide more predictable benefits

5. Comprehensive Channel Cleanout

System-wide channel dredging and debris removal

NOT RECOMMENDED

Concerns:

May increase water levels downstream during high flows
Risk of head cutting and bank failures
Could threaten nearby levee systems
Limited impact on flood duration

6. Channel Straightening

Create cutoffs to straighten meandering river sections

NOT RECOMMENDED

Risks:

Continued channel degradation and head cutting
Bank failures threatening levee systems
High construction and maintenance costs
Disruption of habitat and floodplain function

Note: Only considered feasible in areas with large floodplain width on both sides

7. Clearwater Dam Operational Changes

Modify dam operations to reduce downstream flooding

NOT EFFECTIVE

Analysis Results:

Attempts to limit releases increase uncontrolled spillage
Increases risk to dam safety
Results in higher peak releases and more days above critical elevations
No benefit to downstream areas

Next Steps

The study recommends a combined approach focusing on:

Immediate: Standard channel maintenance and debris removal for safety
Short-term: Implementation of two-stage ditches and local drainage improvements
Long-term: Consideration of strategic levee setbacks where feasible

Project Information

U.S. Army Corps of Engineers
Little Rock District
Hydraulics and Technical Services Branch

700 W. Capitol Ave
Little Rock, AR 72201

For additional information about this study, please contact the Little Rock District.

Contact Us

General Questions
501-324-5551
Locks and Dams
501-324-5739
Regulatory
501-324-5295