Iowa Watersheds Project | Soap Chequest 2.7.13
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Transcript of Iowa Watersheds Project | Soap Chequest 2.7.13
Iowa Watersheds Project
Project Update:Soap Creek & Chequest Creek
Larry WeberDirector, IIHR – Hydroscience and Engineering
February 7, 2013
Quarterly Update
Iowa Watersheds Project Overview/Review – Phases I & II
Project Timeline
Early Results from Phase I Modeling
Prioritizing HUC 12s for Watershed Projects
Iowa Watershed ProjectsOverview
To plan, implement, and evaluate watershed projects to lessen the severity and frequency of flooding in Iowa
Identified four partner watersheds in May 2012
Overview
Hydrologic model development Identify areas in subwatersheds for project
construction
Phase I: Hydrologic Assessment
Engage landowners to construct projects in subwatersheds
Projects may include:- Active and passive distributed storage, floodplain restoration or easements, buffer strip installation and enhancement, advanced tile drainage
Monitor impact of constructed projects and evaluate feasibility at a larger scale
Phase II: Project Construction & Implementation
Engagement of watershed boards and private land owners will be vital
to project success
Project TimelinePhase IJune 2012 Watershed kickoff meetings
Commence data collection and watershed modeling
Fall 2012 Meeting to discuss model development & data needs
Winter 2013
Meeting to discuss initial findings of hydrologic modeling & community/landowner engagement in the watershed
Spring 2013
Continue quarterly meetings to discuss modeling progress, potential projects for implementation, share progress on other watershed activities
Fall 2013 Complete and present hydrologic assessment
Winter 2014
Finalize hydrologic assessment report
Project TimelinePhase IIFebruary 19, 2013 Identify HUC 8s for Phase II
Spring 2013 Identify HUC 12s for project construction, WMA begins dialogue with IEDA regarding Phase II funds
Summer & Fall 2013
Explore project locations, commence project design
Winter & Spring 2014
Design projects
Summer 2014 – Summer 2015
Construct projects
Summer 2014 – 2017
Monitor & assess projects
Summer 2017 Finalize Phase II report
Phase I: Hydrologic AssessmentHydrologic models have been developed for Soap
and Chequest Creek to estimate and understand watershed response to rainfall events
Evaluation of existing structures in Soap Creek to quantify water quantity impact and applicability to other watersheds
Identify areas where additional projects may reduce flood damages downstream
Soap Creek302 sub-basins
Chequest Creek 267 sub-basins
Break down structures into groups based on construction year:
1992-1993 12 Structures1994-1999 33 Structures2000-2005 43 Structures2005-2008 22 Structures2009-2012 22 Structures
Total: 132 Structures
Pond Construction
Pond Construction:Prior to 1993
1993 Total Area (km2) Total Area (mi2) Total Area (acres)647.497 250 160000
% Controlled Area Controlled (km2) Area Controlled (mi2) Acrea Controlled (acres)1.81% 11.69 4.51 2889.01
Pond Construction:Prior to 2005
2005 Total Area (km2) Total Area (mi2) Total Area (acres)647.497 250 160000
% Controlled Area Controlled (km2) Area Controlled (mi2) Acrea Controlled (acres)15.29% 98.99 38.22 24460.09
Pond Construction:Prior to 2008
2008 Total Area (km2) Total Area (mi2) Total Area (acres)647.497 250 160000
% Controlled Area Controlled (km2) Area Controlled (mi2) Acrea Controlled (acres)18.83% 121.93 47.08 30129.55
Pond Construction:Prior to 2012
2012 Total Area (km2) Total Area (mi2) Total Area (acres)647.497 250 160000
% Controlled Area Controlled (km2) Area Controlled (mi2) Acrea Controlled (acres)23.81% 154.18 59.53 38097.58
Pond Construction
Design StormsModeled 24-hour storms at the following return periods
2 yr: 3 inches5 yr: 3.5 inches10 yr: 4.75 inches25 yr: 5.5 inches50 yr: 6.5 inches100 yr: 7.5 inches
Results 100 yr storm, 7.5” of rain
Reduction57.67%
Reduction35.74%
Reduction18.31%
Reduction26.30%
Reduction21.09%
Reduction29.69%
100 yr storm, 7.5” of rain
Pond Storage 100 yr storm, 7.5” of rain
Pond Storage 100 yr storm, 7.5” of rain
Peak Pond Storage 100 yr storm, 7.5” of rain
Gauge data collected from four sites:Hourly Data - OttumwaDaily Data - Albia, Bloomfield, and
Centerville
Historical Rain Events
June 2-9, 1993 7.36” in Bloomfield 2”-4” in Albia, Centerville, and Ottumwa
July 7-17, 1993 2”-5” across area
June 3-13, 2008 4.5”-7” across area
June 9-20, 2011 10.63” measured in Ottumwa 4”-8” measured in Albia, Centerville, and Bloomfield
2” fell in watersheds on 9-10 June, 2011 2-6” additional fell during 13-15 June, 2011
Historical Rain Events
Gridded rainfall from historical rain events
Historical Rain Event: June 13-14, 2011
Historical Rain Event: June 13-14, 2011
Rainfall Distribution: June 13-14, 2011
June 13-19, 2011
Reduction58.33%
Reduction29.00%
Reduction18.52%
Reduction27.98%
Reduction3.81%
Reduction8.09%
Results June 13-19, 2011
Results June 13-19, 2011
Pond Storage, 2011
Pond Storage, 2011
Peak Pond Storage, 2011
Soap & Chequest WatershedsSix IFC stream-stage sensors added in November 2012
Prioritizing HUC 12s
Watershed with intrinsic public value/awareness
Headwater regions of the watershedHigh runoff & localized flooding observed
during rainstorms Damages to property – residential, commercial, &
repetitive crop damages Washed out / impassable roadways
Team of diverse stakeholders, technical expertise and local leadership Local, state and federal organizations
Watershed projects, past and proposedLandowner and producer willingness to
participate
Positive Characteristics