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Long Term Flood Solutions Plan for the Basin Planning for the 20% Flow Reduction Distributed Detention Strategies for Individual Watershed DistrictsHalstad.

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Presentation on theme: "Long Term Flood Solutions Plan for the Basin Planning for the 20% Flow Reduction Distributed Detention Strategies for Individual Watershed DistrictsHalstad."— Presentation transcript:

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2 Long Term Flood Solutions Plan for the Basin Planning for the 20% Flow Reduction Distributed Detention Strategies for Individual Watershed DistrictsHalstad Upstream Retention Study Water Quality Improvement Potential

3  A plan developed by the Red River Basin Commission to reduce future flood damages by reducing flows  Accomplished primarily by detaining/retaining water upstream  Requires construction of multiple storage facilities (impoundments) distributed throughout the basin Basin wide Flow Reduction Strategy

4 Primary Criteria Set a goal high enough to significantly reduce flood damages Set it low enough to be considered doable and reasonably foreseeable Initial Goal of 20% peak flow reduction along the entire length of the River Would likely have prevented the 1997 disaster in Grand Forks / East Grand Forks Considered doable by the committee, which included engineers representing tributary watersheds Not a “Make or Break” goal Lesser reductions will provide incremental benefits Greater reductions will increase benefits

5 How much storage would be required?? No suitable hydraulic model of the entire Red River Mainstem existed in 2005 to answer that question RRBC FDR Committee, with assistance from consultants on contract, set out to develop a model… That could dynamically account for both flow and storage across the broad valley as the flood wave moves north

6  The Basin Commission next encouraged each water district to identify storage it could build to meet its flow reduction allocation  Existing hydrologic models (where available) were used by local water management engineers to prepare revised tributary hydrographs to the Red River that would result from the planned storage Identifying Storage Potential

7 26 storage sites were identified to meet the 20% reduction goal at Wahpeton including one (North Ottawa) that has been constructed since 1997 and one hypothetical site in South Dakota.  The constructed storage volume would be 125,000 ac-ft of which 101,000 ac-ft would be gate controlled.  This compares to a flow reduction allocation of 98,000 ac-ft.  This suggests that total constructed storage may need to be about 25% greater than the flow reduction allocation or about equal to the gate controlled portion as expected. BOIS DE SIOUX WATERSHED 2010 Flow Reduction Strategy

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10  Completing and refining the tributary flow reduction plans clearly required new and improved hydrologic models for many tributary areas.  Recently collected LIDAR data greatly improves potential model accuracy and detail.  New HEC-HMS models are nearly completed using consistent and coordinated methodologies for all US tributaries.  New HEC-HMS models are being developed north to the border and beyond as LIDAR data becomes available. Improved Hydrologic Models

11  Using the new models, watershed are identifying sites that would meet their allocated flow reductions. Refined Tributary flow Reduction Plans

12 Background Information RRBMI LiDAR Multiple Partners, Led by IWI Phase 1 - HEC-HMS Existing Conditions Communities of Fargo and Moorhead Site Identification Process and Level of Detail Minnesota Tributary Expanded Distributed Detention Strategies Funded By: Red River Watershed Management Board (Minnesota) Red River Basin Commission Buffalo-Red River Watershed District North Dakota Tributary Comprehensive Detention Plans Funded By: Red River Joint Water Resource District (ND) Local Water Resource Districts North Dakota State Water Commission

13 North Ottawa Impoundment Project Bois de Sioux Watershed District (Minnesota) Controls 75 square miles 16,000 Ac-Ft of gated storage

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16 Approximately 25 Locations 300K A-F Total 157K A-F Gated 143K A-F Ungated

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18 IWI Project Planning Tool Development - $180,000 Distributed Detention Plan Development - $480,000 Total -$660,000 Funded By: Red River Watershed Management Board$617,000 Buffalo-Red River Watershed District$21,600 Red River Basin Commission (FMDA)$21,600

19 TOTAL COST$1,700,000 NDSWC (50%)$850,000 RRJWRD (32.5% - 50%)$710,000 Local (0% %)$140,000

20 Methodology – Site Identification Criteria Control minimum of 20 square miles Avoid impacts to residential structures / infrastructure Store a minimum of 3 inches of runoff Avoid mainstem locations in lower 2/3 of watershed Primarily select off-channel & stream locations Reasonable levee heights & inundation impacts Modeling Assumptions Gated with E.S. 5 feet below top of levee Dry storage, no conservation pools

21 Elm River Traill Co. WRD Cass Co. Joint WRD Rush River Cass Co. Joint WRD Maple River Maple River WRD Lower Sheyenne Cass Co. Joint WRD Wild Rice River Richland Co. WRD Cass Co. Joint WRD

22 100 ND Detention Site Options Identified 7 Elm River 3 Rush River 40 Maple River 20 Lower Sheyenne 30 Wild Rice Summary of Results for 100-yr Snowmelt Tributary peak reductions in excess of 35% possible Flood volume reductions in excess of 20% possible LTFS tributary goals can be achieved Off-channel sites needed to control peaks in many cases

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24 To provide information to advance the Red River Basin Commission’s Long Term Flood Solutions Report To provide assistance to the Fargo-Moorhead Diversion Authority on how to prioritize/allocate the approved $25 Million in Detention Funding NOT to determine how upstream detention would alter current Fargo-Moorhead Metro Diversion Design

25 Related Studies Utilized HEC-RAS Model Development (Phase 7) – Fargo-Moorhead Metro Project Phase 1 - HEC-HMS Existing Conditions – US Army Corps of Engineers Basinwide Feasibility Study Detention Sites Provided By: MN Expanded Distributed Detention Strategy Funded By: Red River Watershed Management Board (Minnesota) Red River Basin Commission Buffalo-Red River Watershed District ND Comprehensive Detention Plan Funded By: Red River Joint Water Resource District (ND) Local Water Resource Districts North Dakota State Water Commission

26 Sites Identified for Local Benefits First Sites Identified by Local Watershed Districts & Water Resource Districts Local Benefits First Sites Initially Empty (No Normal Pool) Drawdown of Gated Storage Not Considered All Detention Sites Built Full Implementation Required to Generate Reported Benefits Assumes full implementation Conceptual Impoundment Locations No Landowner Involvement Ability to Implement No Cost Evaluations Limited Site Data Modeling based on synthetic 100-year flood scenario Based on Uniform/Standardized Runoff Assumption Non-uniform runoff expected during actual events Drawdown of Gated Storage Not Considered Modeling completed based on the existing Red River condition Potential changes to FM Diversion Project not evaluated

27 Watershed Contributing Area Contributing Area of Proposed Sites Number of Sites Included Total Utilized Storage* Gated Storage* Utilized Ungated Storage* Event Peak Inundation Area Square Miles Acre-Feet Acres Bois De Sioux1, ,20088,10018,10020,130 Otter Tail1, ,4002,5003,9001,530 Upper Red River ,80029,3008,5009,340 Wild Rice (ND)2, ,60064,70010,90017,870 Maple/Rush/Sheyenne5, ,50098,80021,70020,050 Buffalo ,00025,40011,60011,140 Elm (Red River Ungaged)478 (255)109323,90018,9005,0004,780 Wild Rice (MN)1, ,700101,00022,70018,340 Marsh ,20026,8001,4004,590 Totals14,6222, ,300455,500103,800107,770 *Presented storage volumes correlate to runoff volume detained during the analyzed 4-day Initial Melt Progression Event. One Scenario Resulting in a 20% Peak Flow Reduction 96 Locally Identified Sites

28 23% Peak Flow Reduction 10% Flood Volume Reduction

29 Available for Download at Red River mainstem 20% peak flow reduction is attainable for the analyzed event Differing events will result in varying levels of flow reduction benefit Estimated Stage Reduction of 1.0’ at Halstad, MN (1.3’ at Fargo, ND) 96 Locally Identified Sites were used to for the proposed HUR Scenario Stores a portion of runoff from 2,650 square miles 560,000 Acre-Feet of Storage (455,000 Acre-Feet Gated) 107,800 Acres Inundated within Storage Sites (170± Sections) Conceptual Locations Standardized Melt Progression Event represents one scenario to produce a 100-year flood at Fargo, ND Varying events may also result in a 100-year flood at Fargo, ND Provides tools necessary to evaluate specific projects for regional performance The HUR Study does NOT evaluate retention as an alternative to the current F-M Metro Flood Control Project

30 Funding Availability Magnitude of funds need to fully implement Funding eligibility (Project Development, Land Acquisition, etc…) Non-traditional funding partners (FM Diversion Authority, Farm Bill, etc…) Land Acquisition Methods – Site Specific Location Education Proactive Acquisition Condemnation Locally Acceptable vs Permit-ability Location, location, location…

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32 What can we do to maximize Nutrient Capture at Impoundment Sites

33 Minnesota, North Dakota and Manitoba all developing Nutrient Reduction Strategies MPCA released Nutrient Reduction Strategy Non-point Sources contribute 82% Phosphorus and 91% Nitrogen Phosphorus Reduction Goals for Red River will be similar to Mississippi River Basin 45%

34  Design, Construct and Operate Treatment Cells within North Ottawa Impoundment with Bois De Sioux WD and their engineer Charlie Anderson, WSN  Develop surface water monitoring protocol to measure nutrient loading and removal effectiveness  Harvest cattails in individual cells at different times of the year and optimize nutrient capture and removal  Evaluate potential uses of cattails with Dr. Dan Svedarsky, University of MN - Crookston North Ottawa Project

35 Incorporate Detailed Monitoring System North Ottawa Unique “Field Scale” Experimental Opportunity “Closed System” Allows Detailed Upstream, Within Treatment Cell, and Downstream Monitoring Development of Phosphorus Budget, Measurable/Quantifiable Results

36 Develop and maximize large scale Nutrient Reduction Strategy Utilizing land already set aside for Flood Control Purposes Use of treatment cells as a strategy to maximize Nutrient Reduction in High Loading Watersheds Scalable, potentially significant Phosphorus Reduction Tool 600 acres cattail harvested will remove 6600 pounds phosphorus,100% average load 75 square mile watershed above North Ottawa This project is funded by MPCA 319 Fund and Mn Legislative/Citizen Commission on Minnesota Resources, future funding requests will be submitted to continue this work


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