Watershed Specific Recommendations

Flatfork Creek - Fall Creek Watershed

	The following discussion is based on drainage problems or complaints that were identified in the Flatfork Creek - Fall Creek Watershed for existing and future concerns noted in Chapter 2 and Chapter 3 of this Master Plan. Each issue, concern, or opportunity is restated in simple terms, and then followed by an evaluation of the promising alternative solutions (if applicable), a discussion of the recommended improvements, and an estimate of the associated costs. The cost estimates are provided for budgeting purposes only. A copy of these cost calculations is included in Appendix 4. They are based on field observations and limited data. Actual cost of construction and design may be more or less depending on additional information that would be gathered during the design phase. For the issues that had several promising solutions, CBBEL explored the solutions and narrowed them down to the best solution with input from the Town of Fishers staff. Table 5-2 at the end of this Chapter provides a summary of the recommended improvements. Chapter 6 of this Master Plan will focus on implementation of the recommendations identified.

The following discussion is based on drainage problems or complaints that were identified in the Flatfork Creek - Fall Creek Watershed for existing and future concerns noted in Chapter 2 and Chapter 3 of this Master Plan.

Each issue, concern, or opportunity is restated in simple terms, and then followed by an evaluation of the promising alternative solutions (if applicable), a discussion of the recommended improvements, and an estimate of the associated costs. The cost estimates are provided for budgeting purposes only. A copy of these cost calculations is included in Appendix 4. They are based on field observations and limited data. Actual cost of construction and design may be more or less depending on additional information that would be gathered during the design phase. For the issues that had several promising solutions, CBBEL explored the solutions and narrowed them down to the best solution with input from the Town of Fishers staff. Table 5-2 at the end of this Chapter provides a summary of the recommended improvements. Chapter 6 of this Master Plan will focus on implementation of the recommendations identified.

Other Issues (3)

	FC1 Issue The Zone A delineation along Fall Creek near the Madison County line appears to miss some floodplain area. It is therefore possible that development would be improperly allowed in the actual floodplain. Recommended Improvement It is recommended that the downstream detailed study along Fall Creek be continued through this reach to determine the floodway and floodplain boundaries. This delineation should then be submitted to FEMA for a LOMR. The approximate study of Thor Run should also be redone based on the Hamilton County 1 foot contour mapping and submitted to FEMA for revision of the FIS maps. The estimated cost of these 2 studies is $10,000.

FC1

Issue

The Zone A delineation along Fall Creek near the Madison County line appears to miss some floodplain area. It is therefore possible that development would be improperly allowed in the actual floodplain.

Recommended Improvement

It is recommended that the downstream detailed study along Fall Creek be continued through this reach to determine the floodway and floodplain boundaries. This delineation should then be submitted to FEMA for a LOMR. The approximate study of Thor Run should also be redone based on the Hamilton County 1 foot contour mapping and submitted to FEMA for revision of the FIS maps. The estimated cost of these 2 studies is $10,000.

Recommend detailed study for this portion of Fall Creek.
FIS Delineation Issues

FC2

Issue

Based on the hydrologic analysis completed for the current Hancock County Flood Insurance Study, existing condition flow rates in portions of the Flatfork Creek watershed are lower than the default Town or County release rates for new development in Hamilton County and upstream in Hancock County. Proposed development is, as a result, allowed to increase the runoff from any given site in the affected subwatersheds.

Recommended Improvement

Based on the goals and performance criteria established for this Master Plan (Chapter 4), it is recommended that the Town coordinate with the Hamilton County Surveyor’s Office and Hancock County Surveyor’s Office to add the calculated existing condition flow rates from the FIS hydrologic study to the applicable ordinances and the County Surveyor’s list of restrictive release rate watersheds. These rates are 0.023 cfs per acre and 0.055 cfs per acre for the 0-10% and 10- 1% annual chance floods, respectively. The staff time required for this coordination is estimated to be $1,000. (FIS Delineation Issues)

Recommend utilization of EPA's SUSTAIN model to identify BMPs.

FC3

Issue

Water quality samples collected on Flatfork Creek at 101st Street (Site 9) indicated the 5th poorest overall water quality of the 10 sites studied as part of this Master Plan. Appendix 3 contains a summary of the water quality data collected.

Recommended Improvement

To address this issue the watershed should be studied to identify retrofit and new design opportunities for green infrastructure to improve water quality. Potential BMPs, project sites, pollutant loads, and volume reductions could be modeled using EPA’s recently released SUSTAIN (System for Urban Stormwater Treatment and Analysis Integration Model) or similar tool. Based on the water quality data collected, it is a high priority recommendation for implementation.

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