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South Dakota Department of Transportation
Request for Research Proposal

Project SD2013-03

TITLE: Rainfall-Runoff Modeling for Improved peak-Flow Estimates in the Black Hills of SD

Problem Description:Peak-flow characteristics for “gaged” streams typically are estimated by the U.S. Geological Survey (USGS) in statewide projects using probability analyses of datasets of the largest annual peak flow for streamgages (see Error bars about the estimates (uncertainties) for any stream may be relatively small for the smaller recurrence intervals, such as the 2-year through 10- or 25-year floods, but uncertainties generally increase substantially for increasing recurrence intervals. These “at-site” estimates typically are then used in statewide “regionalization” projects for estimating peak-flow characteristics for ungaged streams, where further increases in uncertainties are inherent. Peak-flow characterization is especially complex in the Black Hills region, where geology, climate, and topography can vary substantially across small spatial scales. In this region, classifying many streamgages based on proximity for regionalization estimates may not be the most accurate approach. An alternative approach using design rainfall events with known frequency estimates to drive calibrated hydrologic models may result in more accurate estimation of peak-flow frequencies, regardless of the observed flow records. Various types of rainfall-runoff modeling (such as HEC-HMS) can be used to estimate peak-flow characteristics for many applications, but typically are considered to be less reliable than estimates for gaged datasets, when available. However, rainfall-runoff modeling can perform very well in accounting for watershed characteristics and, especially when calibrated using available precipitation and streamflow data, could provide an excellent tool for improving peak-flow estimates for the Black Hills area. In particular, modeling could be used to identify specific watersheds with distinctively different potential for peak-flow generation and to which different approaches for peak-flow characterization could be applied.
Urgency:   The SDDOT Bridge Program and USGS currently are in the initial stages of a multi-year, two-phase project for (1) a statewide update of at-site peak-flow frequency estimates for streamgages and (2) a subsequent regionalization phase for estimating peak-flow characteristics for ungaged streams. It is anticipated that modeling results would provide direct and timely support to both phases by helping address the extreme complexity of Black Hills sites lacking gaged records of large floods.

Literature Summary:   Abundant literature exists regarding use of rainfall runoff modeling for developing synthetic hydrographs and for estimating peak-flow characteristics, especially for urban settings. USGS has published literally hundreds of reports regarding application of standard approaches that typically involve probability analyses of peak-flow data sets. However, a cursory review indicates that literature is extremely sparse regarding use of rainfall/runoff modeling as a tool in developing peak-flow estimates in conjunction with typical probability analyses of peak-flow data sets, and the sparse existing literature commonly deals only with urban settings.

Are Research results already available? False  
If so, how can SDDOT use these results?

In summary, is research needed? True  
Explain: Many advances have been made in recent years in addressing the issues associated with the extreme complexities of peak-flow frequency analyses for the Black Hills area. Recent advances have included innovative approaches for at-site frequency analyses and results from paleoflood investigations that have substantially improved the knowledge base regarding the relative frequency of occurrence of extreme flood events such as those of 1972. The proposed research would provide an important improvement to peak-flow estimation for the area.

Implementation:   This research effort will directly support both phases of the project that the SDDOT Bridge Program and USGS are just initiating (see Urgency section above.

Funds Available:   $150,000.00

Contract Period:   24 months

SDDOT Involvement:   Needs for assistance from SDDOT are not anticipated; however, through the Project Technical Panel, SDDOT will be prepared to supply any data that might be deemed useful to the project efforts.

General Information:  The Office of Research of the South Dakota Department of Transportation (SDDOT) solicits proposals from colleges, universities, research institutes, foundations, engineering or other consultants, federal/state/local agencies or others who possess extensive, demonstrated capability and experience in the subject area.

Proposal Deadline:  Proposals are due at the following address by 5:00 pm on 12/31/2015:
South Dakota Department of Transportation
Office of Research Room 164
700 East Broadway Avenue
Pierre, South Dakota  57501-2586

Proposers will be notified of the results of the selection in writing no later than 01/17/2014.

Anticipated Start Date:   01/17/2014

The proposal deadline is firm. Extensions will not be granted. 6 copies of the proposal must be submitted.

Project Management:   John Foster has responsibility for management of this project, and can be reached at 605-773-6234.

Research Objectives:
1  Investigate the feasibility of applying selected rainfall-runoff modeling approaches in estimating peak-flow characteristics associated with the complex hydrology in the Black Hills area.
2  Apply, test, and validate accuracy of selected modeling approach for improving peak-flow characterization for the Black Hills area.

Research Tasks:
1  Review and summarize literature and consult with agencies such as Federal Emergency Management Agency and U.S. Army Corps of Engineers that commonly use rainfall-runoff modeling for estimating peak-flow characteristics for engineering applications.
2  Meet with the project’s technical panel to review the project scope and work plan.
3  Identify and evaluate existing rainfall-runoff modeling approaches with potential application to the Black Hills area.
4  Identify and evaluate potential watersheds and available datasets for the Black Hills area suitable for application of selected modeling approaches.
5  Meet with the project’s Technical Panel to review results of tasks 1-4 and to confirm plans for calibrating, applying, and validating selected rainfall-runoff modeling approaches.
6  Calibrate and apply the selected rainfall-runoff modeling approaches to accomplish improved peak-flow characterization for the Black Hills area.
7  Evaluate the accuracy of selected modeling approaches against known precipitation and streamflow inputs.
8  Prepare a final report summarizing research methodology, findings, preliminary conclusions, and recommendations.
9  Meet with the project’s Technical Panel to review results, findings, and recommendations.
10  Make an executive presentation to the South Dakota Department of Transportation Research Review Board at the conclusion of the project.

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