This document provides an update on the HGS model development and Phase II project. It includes the following key points: - The physically-based HGS model accounts for all surface and subsurface water interactions within the Turkey River Watershed, which contains over 12,000 nodes. The model considers factors like evapotranspiration, precipitation, stream flow, land use, and topography. - Monitoring of stream flow at key locations will help establish baseline conditions and assess the impact of implemented projects on flood reduction and water quality. Three monitoring platforms will be installed to validate precipitation events. - Phase II will focus on selecting project sites, designing and constructing projects like ponds, wetlands, and floodplain easements

3.  HGS update – Model development, inputs,




outputs
Phase II project types, site selection
Monitoring
Timeline
Next Steps
Beaver
Creek
Otter Creek
South
Chequest
Acres
11,089
30,213
20,072
County
Floyd
Chickasaw
Fayette
Davis
West Union
Elgin
n/a
Communities Bassett
Colwell

4.  Physically-based model accounts for all surface
& subsurface interactions

6. West Union
OTTER CREEK
Turkey River
Watershed
>12,000 nodes
Elgin

7.  Evapotranspiration
 Precipitation
 Stream flow, discharge

8. Land use
Topography

12. Surface Water Hydrology
USGS 05411850 Turkey River near Eldorado, IA
5000.0
4500.0
Daily Mean Q (cfs)
4000.0
3500.0
3000.0
2500.0
6/9/2008
6/8/2008
4/25/2008
6/10/2008
4/26/2008
6/13/2008
6/12/2008
4/19/2008
6/11/2008
35495.7
13810.7
10895.2
10740.6
9122.1
7989.9
6684.8
5267.9
5249.0
2000.0
1500.0
1000.0
500.0
0.0
10/01/07 06/07/08 02/12/09 10/20/09 06/27/10 03/04/11 11/09/11 07/16/12 03/23/13
Date
Otter Creek at Elgin / Estimated with Regional Formulas
500.0
6/9/2008
6/8/2008
1336.4
530.4
Daily Mean Q (cfs)
400.0
300.0
200.0
100.0
0.0
10/01/07 06/07/08 02/12/09 10/20/09 06/27/10 03/04/11 11/09/11 07/16/12 03/23/13
Date
Computing Daily Mean Streamflow at Ungaged Locations in Iowa
by using the Flow Anywhere and Flow Duration Curve Transfer
Statistical Methods
By S. Mike Linhart, Jon F. Nania, Curtis L. Sanders, Jr., and Stacey A.
Archfield

13. HGS – June 2008 Scenario
West Union

14. HGS – June 2008 Scenario
14

15.  Existing project locations
 Bridge information / design
 Hydraulic structures
 Low-head dams
 Water quality / Water quantity
monitoring
 Water /wastewater plant

16.  Establish baseline conditions in HUC 12s
 Monitor the impact of projects
 Publically-accessible data

17.  Ground validation of precipitation events:
 Rainfall totals
 Soil moisture
 Soil temperature
 3 platforms distributed across HUC 12

20.  Check with Carrie on nutrient
gage update for Otter Creek

21.  Flood reduction benefits:
 Ponds
 Wetlands
 Floodplain easements
 Controlled drainage buffer strips
 Projects approved in consultation with
Iowa Flood Center

22. Phase II
Summer & Fall 2013
Explore project locations,
commence project design, deploy
monitoring equipment
Winter & Spring 2014
Design projects
Summer 2014 – Summer
2015
Construct projects
Summer 2013– 2017
Monitor & assess
Summer 2017
Finalize Phase II report
Phase II
Fall/Winter 2013
Complete hydrologic assessment

24. Long term effective precipitation ~ 12.1 in/yr

25. Next Steps
• Evapotranspiration (based on land use maps and literature)
• Snow melting?
• Subsurface/Infiltration (properties from driller’s log and
soil type maps)
• Go from point precipitation to areal precipitation. Radar?
• Work on the DEM
• Calibrate against daily Q from regional formulas?
25