Memorandum Agenda Item 24 03/29,30, 1999

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• 3. Since Urban Drainage prepares future conditions studies and FEMA requires existing • conditions studies, how will the differences be resolved? FEMA and Urban Drainage have already negotiated a specific agreement regarding this issue as it pertains to Boxelder Creek in Adams and Arapahoe Counties, and that agreement will probably serve as the template for answering the above question. They have agreed that if future conditions flows are less than 130% of existing conditions flows, the future conditions flows will be used. If the future conditions flows are larger than 130%, Urban Drainage will map existing conditions floodplains for FEMA. Since Urban Drainage maps future conditions floodplains, they and FEMA will negotiate technical procedures for mapping both floodplains on the same maps. Urban Drainage and FEMA will also negotiate specific technical procedures for "judging the reasonableness of District hydrology", in other words, how to compare District flows to some agreed-upon standards for acceptable flows. 4. How will the CTC agreement assure compliance with the CWCB's Rules and Regulations? Currently FEMA's study process includes no specific procedure beyond coordination meetings and submittal of copies of draft study documents for CWCB comment to involve the CWCB in the preparation of Flood Insurance Studies. There is no formal agreement that studies will comply with the CWCB's Rules and Regulations. Generally, when the CWCB has made requests and suggestions for corrections/revisions, they have been honored by FEMA and its consultants. It is assumed that the same would be true with Urban Drainage, an agency with a • long history of coordination and cooperation with the CWCB. It is recommended that in the future, all FEMA study contracts include a specific schedule of review mileposts: a) hydrology, b) topographic mapping, c) selection and calibration of hydraulic models and procedures, d) preliminary hydraulic results, e) floodplain delineations, and f) final draft of full report and maps. Formal meetings could be held at three important points in the study process: Study Point 1 The end of mileposts a), b) and c); Study Point 2 The end of mileposts d) and e); Study Point 3 The end of milepost f). Requiring verbal endorsement by FEMA, the CWCB, the local government(s), and the study contractor(including Urban Drainage) at each milepost would involve all affected parties at each critical step in the study process. Such a mechanism would not require the CWCB's signature in • the CTC agreement, but it would ensure that all parties, including those not signing the agreements, knew when each step in the study was to be completed and knew that each party was involved in reviewing the work. That would assure the CWCB that at each step compliance with its Rules and Regulations was being considered.