Kankakee River Flood and Sediment Management Work Plan Iroquois County Summary Siavash Beik and Robert Barr Public Information Meeting February 13, 2020
Kankakee River Flood & Sediment Management Work Plan – Diagnose the Root Causes of Erosion, Sedimentation, and Flooding through Detailed Field and Desktop Assessment – Communicate the Extent of Existing Risks and Expected Trends (Changing Climate) – Identify Strategies for Addressing the Issues in a System-wide Approach – Develop a Work Plan for Implementing Various Strategies Specific to Each Area A Joint Indiana – Illinois Effort to Address a Legacy Problem Within the Watershed (Main Stem Facing Both States! Reaches, Laterals, Urban Areas, Ag Areas)
What we heard in Illinois: • Sand load is increasing • More sand bars are developing • Channel in Momence area is shifting • Flooding is increasing in Momence, Aroma Park, and Watseka • Dredging and tree removal in Indiana are concerns because of their potential for increasing flows and sediment
RIVER HISTORY
Iroquois River upstream from Rensselaer, IN
Iroquois River upstream from Rensselaer, IN
Iroquois River downstream from Rensselaer to downstream from Brook, IN
Iroquois River downstream from Rensselaer
Iroquois River downstream from Brook, IN to Watseka, IL
Iroquois River downstream from Brook, IN to Watseka, IL
Iroquois River downstream from Watseka to Aroma Park, IL
Iroquois River downstream from Watseka, IL
KEY FINDINGS
Discharge comparison, Kankakee River and Iroquois River
Sediment Load (tons) Year Davis Oak Grove Knox Brems Shelby Momence Foresman Chebanse 542 mi 2 377 mi 2 435 mi 2 438 mi 2 1,779 mi 2 2,294 mi 2 449 mi 2 2,091 mi 2 2013 - 22,700 73,600 89,900 - - - - 2014 23,700 15,300 37,700 17,800 - - - - 2015 23,700 20,200 45,900 34,600 122,300 - 31,800 - 2016 27,000 17,200 41,800 36,800 105,000 - 25,000 - 2017 27,800 21,800 56,700 63,200 91,000 - 32,100 - 2018 29,100 29,200 102,900 114,400 117,600 - 36,200 - AVG 26,300 21,100 59,800 59,400 109,000 204,000 31,300 391,100 Sediment Budget for Kankakee River System
Changes at In-channel Islands near Aroma Park
Rill development and headward erosion, Newton County, IN
Rill development and headward erosion near Watseka, Iroquois County, IL
EXTENT OF EXISTING FLOOD RISKS AND TRENDS
EXTENT OF EXISTING FLOOD RISKS AND TRENDS
Observed Decadal Trend of Heavy Observed % Change in Total Annual Precipitation Precipitation (2-day, 5-year RI) in Midwest Falling in the Heaviest 1% of Events (1958 – 2016) (1901-2012 compared with 1901-1960) Source: USGRP, 2014, Third National Climate Source: USGRP, 2018, Fourth National Climate Assessment (adapted from Kunkel et al. 2013) Assessment.
Recorded Peak Annual Discharges at Iroquois River at Iroquois, IL USGS Gage (88% Increase!)
Recorded Peak Annual Discharges at Sugar Creek at Milford, IL USGS Gage (20% Increase!)
Recorded Peak Annual Discharges at Iroquois River at Chebanse, IL USGS Gage (81% Increase!)
Recorded Peak Annual Discharges at Kankakee River at Wilmington, IL USGS Gage (122% Increase!)
Why are Peak flows and Average daily Flow Volumes Increasing? Increased rainfall depths and intensities due to climate change Uncompensated Impacts of urban development Observed % Change in Total Annual Precipitation Falling in the Heaviest 1% of Events (1958 – 2016) Increased agricultural tiling and surface draining projects (some in response to increasing rainfalls!) Extensive tile drainage
How Do These Increasing Trends Affect Management Strategies? “Controlling” flooding by traditional structural alternatives is no longer feasible or prudent (moving target) Strategies have to be cognizant of continued increase and fluctuations in flows (management versus elimination of hazards) Nature-based solutions can better cope with changing climate and fluctuations in flow Minimizing impacts of agricultural and urban development has been and will become even more crucial
RECOMMENDATIONS
Addressing Systemic Flooding and Sedimentation in the Face of a Changing Climate 1. Adaptation Recognizing that flooding is going to occur and taking steps to reduce existing and future vulnerabilities to reduce pain and suffering 2. Mitigation Reducing the stressors to the system and the Flooding and Sedimentation sources to the extent possible through common sense and feasible actions without adverse impact to others
What is No-Adverse-Impact (NAI) No-Adverse-Impact Floodplain Management – ASFPM Defines NAI as: “… an approach that ensures the action of any property owner, public or private, does not adversely impact the property and rights of others.” – NAI broadens property rights by protecting the property rights of those that would be adversely impacted by the actions of others. – The 2019 Kankakee Work Plan recommendations are consistent with NAI principles
Recommended Adaptation Strategies for the Iroquois River Watershed Adopt NAI Development Standards for Urban Areas Adopt NAI Standards for New Farm Drainage & Regulated Drain Projects Develop and Implement Community-Specific Flood response Plans Develop and Implement Community-Specific Flood Resilience plans Incentivize Soil Health and cover crop use within the watershed Conduct a Detailed System Assessment and Develop a Work Plan for the Entirety of Iroquois River (including Indiana) Conduct a Detailed System Assessment along Sugar Creek
Recommended Adaptation Strategies (cont.) Develop Flood Response Plans – Flooding, such as that observed in 2018, cannot be prevented – Flood Response Plans help emergency responders with forecasting, detecting, classifying severity, and warning & evacuation priorities associated with an event – In Indiana, IDHS & OCRA were be able to help fund these plans Develop Flood Resilience Plans – Strategies are needed to curb increase in flood vulnerability – Most effective resilience plans offer geographical-specific resilience strategies – In Indiana, FEMA, IDHS, & OCRA were be able to help fund these plans
Recommended Adaptation Strategies (cont.) Adopt Specific Flood Resilience Strategies for Watseka, IL River Corridor To conserve land and prohibit Impact Areas development Vulnerable To protect people, buildings, Developed Areas and facilities in the vulnerable areas and reduce future flood risk Undeveloped High To conserve land and maintain Hazard/Flood the natural and beneficial Storage Areas function of the floodway fringe Moderate Flood To identify areas that are Hazard Areas subject to flooding during an extreme event and to discourage future development in these areas Safer Areas To plan for and promote development in areas that are less vulnerable to future floods Watershed To promote coordination and partnerships and implement practices to slow, spread and infiltrate flood water
Recommended Adaptation Strategies (cont.) Conduct a Detailed System Assessment and Develop a Work Plan for the Entirety of Iroquois River & Sugar Creek – The Iroquois River contributes more Sediment Load (tons/year) 1% AEP water and sediment to the Kankakee DA Location Discharge (mi 2 ) River downstream from the confluence Sand Silt/Clay Total (cfs) than the Kankakee but has been studied much less than the Kankakee Kankakee River above Iroquois 2,378 54,000 176,000 230,000 22,000 – A detailed system assessment of the River Iroquois River (both in Indiana and in Iroquois River at Illinois) as well as along Sugar Creek is 2,137 17,000 402,000 419,000 37,000 mouth needed to address increased peak Wilmington, IL 5,150 76,000 766,000 842,000 85,000 discharges and sediment contributions that impact Watseka, Aroma Park and downstream areas
Recommended Mitigation Strategies for the Iroquois River Watershed Sediment Supply Reduction: Address rill/gully erosion within Iroquois River Watershed (both in Indiana and Illinois) Reduce sediment supply from severely eroded Iroquois River Banks Mitigate Increase in Flows Caused by Tiling and Surface Ditching Construct new storage areas along laterals to Iroquois River both in Indiana and Illinois Implement soil health practices such as cover crops Selective Floodproofing Strategically protect of critical facilities, infrastructures, and roads from flooding through structure-specific perimeter protection & raising roads
Recommended Mitigation Strategies (cont.) Addressing Gully/Rill Erosion along Iroquois River Small Tributaries
Recommended Mitigation Strategies (cont.) Construct off-line Retention or detention storage areas along Laterals – Needed to offset increase in runoff due to past and ongoing land drainage activities in the watershed and/or increased rainfall – Future drainage improvements by farmers or Drainage Boards /Drainage Districts should incorporate detention storage as part of improvement
Summary of Work Plan Components (Plan Sheets) Identified Rill Erosion Site Identified Rill Erosion Site Streambank Stabilization Site
OTHER ALTERNATIVES
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