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Hydrologic and Hydraulic Modeling for Evaluating Alternatives for Managed Connection of the Upper and Lower Cache Rivers
Demissie, Misganaw; Bekele, Elias G.; Lian, Yanqing; Keefer, Laura
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https://hdl.handle.net/2142/18674
Description
- Title
- Hydrologic and Hydraulic Modeling for Evaluating Alternatives for Managed Connection of the Upper and Lower Cache Rivers
- Author(s)
- Demissie, Misganaw
- Bekele, Elias G.
- Lian, Yanqing
- Keefer, Laura
- Issue Date
- 2010-08
- Keyword(s)
- Cache River
- hyrologic modeling
- Abstract
- The Cache River basin, located in southern Illinois, has characteristics unique to the State
of Illinois and nation, with diverse physical, chemical, and biological features that produced a
great diversity of natural communities. Because of these unique characteristics, the Cache River
basin contains some high quality bottomland hardwood forests and wetlands that have been
recognized nationally and internationally (Ramsar Convention, 2009). However, changes in
land-use practices and hydraulic modifications during the last century have significantly
threatened the ecological integrity of some of these valuable habitats and wetlands. Therefore
one of the key goals of resource managers working in the area is to restore the Cache River’s
natural hydrologic character to a level that can sustain a viable ecology throughout the river
corridor.
An essential component of the restoration effort for the Cache River has been the development of detailed hydrologic and hydraulic models to determine water levels associated with proposed restoration measures. These models assist the Cache River Wetlands Joint Venture Partnership (JVP) in the decision-making process of selecting and implementing restoration projects that improve the hydrologic conditions for the natural ecosystem. Hydrologic and hydraulic modeling also allow the JVP to satisfy all regulatory requirements and ensure that natural, agricultural, and social resources are not damaged by flooding induced by modifications to the river system.
Hydrologic and hydraulic models were already developed for the Lower Cache River and are published in a report as a product of Phase I of the project (Demissie et al., 2008). In summary, the Illinois State Water Survey (ISWS) developed calibrated hydrologic and hydraulic models, evaluated the hydrology under current flow conditions and various restoration scenarios, and then compared results to the reference/base condition. The reference/base condition refers to the condition when the hydrology of the Lower Cache River was controlled on the east end by Karnak Levee (composed of two 48-inch gated culverts that prevented flow from Post Creek Cutoff into the Lower Cache River) and on the west end by two in-channel weirs located at Route 37 and west of Long Reach Road, referred to as "Diehl Dam." The current condition is similar to the reference/base condition except for a breach in the Karnak Levee at the former location of the two 48-inch gated culverts.
- Publisher
- Illinois State Water Survey
- Series/Report Name or Number
- ISWS Contract Report CR-2010-06
- Type of Resource
- text
- Language
- en
- Permalink
- http://hdl.handle.net/2142/18674