Assessment of Agricultural Flood Damages Along the James River in South Dakota

Transcription

1 Assessment of Agricultural Flood Damages Along the James River in South Dakota Ron S. Beyer Hydraulic Engineer Omaha District US Army Corps of Engineers 2007 Eastern South Dakota Water Conference October 31, 2007 Slide 1

2 James River AFDAM Study Members James River AFDAM Study Members Ron Beyer Hydraulic Engineer, Hydrology Section, U.S. Army Corps of Engineers, Omaha District Kara Reeves Economist, U.S. Army Corps of Engineers, Omaha District Kevin Adams Hydraulic Engineer, Hydraulics Section, U.S. Army Corps of Engineers, Omaha District Steve Rothe Project Manager, U.S. Army Corps of Engineers, Omaha District Slide 2

3 James River Background Low gradient 134 ft drop in 474 miles below Sand Lake NWR Slide 3

4 James River Background Thousands James River at Redfield, SD USGS Observed Hydrograph Flow, CFS Bank full 10-YR Long duration flat peaked flood hydrographs #of Days Slide 4

5 James River Background James River is a very sinuous prairie stream 60-70% agricultural use in the river valley Slide 5

6 James River Background The result is significant long duration flooding of croplands Slide 6

7 James River Feasibility Study Purpose Study issues related to restoration of ecosystem quality while providing flood control and channel restoration benefits Product will be plans for preferred alternatives for aquatic ecosystem restoration and related purposes. Slide 7

8 AFDAM Model Agricultural Flood Damage Analysis Model Based on AGDAM Model Modified for Omaha District and James River Basin Models historic flow records Estimates Agricultural Damages based on: River Stages and Flows Crop Types/Values/Planting Time Time of Year/ Flood Duration Slide 8

9 AFDAM Model Straightforward approach for gaged locations with long periods of observed flow record Specifically written for the 1989 USACE Recon Study Previous Application on James River 1989 USACE Recon Study Pipestem/Jamestown Water Control Plan Revision (USACE July 2000) Slide 9

10 AFDAM Model Based on Period of Record (Gage Data) Concepts and procedures are straightforward Calculates seasonal and duration aspects Direct calculation of replant, alternate crops and double cropping Slide 10

11 AFDAM Model Components Hydrology Hydraulics Economics Slide 11

12 Gage Records Hydrology USGS daily flow USACE screened flow records (similar to USGS) Nine gages from ND-SD Stateline to Yankton, SD Divide model into 8 reaches Slide 12

13 Stateline Columbia Stratford Redfield Huron Forestburg Scotland Yankton Year Record Slide 13

14 Hydrology Reverse Flow Relationships Columbia Ashton Redfield Power Equation for Negative flow/stage relationships (Q=R*A*B) Slide 14

15 Hydraulics Stage, ft Stage vs. Discharge Rating Curve James R. at Redfield, SD Stage vs. flow rating curves Site Specific ,000 10,000 15,000 20,000 25,000 Flow, cfs Slide 15

16 Stage vs. Flooded Area Curves Over entire reach Stage, ft Hydraulics Stage vs. Flooded Area AFDAM Reach 4 Ashton to Redfield, SD ,000 1,500 2,000 2,500 3,000 Flooded Area, Acres Slide 16

17 Agricultural Data Crop Unit Values Economics Area vs. % Crop Type Relationships Flood Duration vs. % Crop Loss Recovery Period (dry time) Slide 17

18 Economics Crop Values SD Crop Budget crop input costs Prices follow Corps Regulation (USDA) Duration and recovery based on County Ext. Office input and NRCS Land Use from NRCS and USGS remote sensing data Slide 18

19 60 50 Economics % Crop vs Flooded Area Reach 4 % Crop Type Corn Soybeans S.Wheat W.Wheat Hay ,000 1,500 2,000 2,500 3,000 Flooded Area, Acres Slide 19

20 Economics Percent Crop Loss Percent Crop Loss vs. Flood Duration Reach Flood Duration, Days Corn Hay Slide 20

21 Percent Crop Loss Economics Crop Loss Functions Reach 4 Corn Soybeans S.Wheat Hay 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Slide 21

22 Economics Agricultural Data % Crop Value Loss vs. Time of Year Slide 22

23 Economics Other Data Infrastructure Damages Can be included as a ratio of Ag Damages Recreational Use Hunting, Fishing, Camping, etc. Slide 23

24 Economics Model development Remote Sensing Data Application Final Overlay Reach end points Flood profile Land use coverage Slide 24

25 Economics Model development Final GIS Product Acres flooded by crop type Acres flooded per flood event (2-, 10-, 50-, 100-, 500-year) Based on HEC-RAS 100 Year: delineation Reach 4 Ashton to Redfield Crop Type Acres % Coverage Alfalfa Corn Deciduous Forest Emergent Herb Wetlands Grassland, Hay/Pasture, Small G High Intensity Commercial / Ind Soybeans Spring Grains, Fallow Winter Wheat Woody Wetlands Totals Slide 25

26 Results Expected Annual Damage By reach By year Economics Computes Damages Existing/Baseline conditions With project alternatives Adjusts area-damage relationships Slide 26

27 Output EAD Comparison By Reach Expected Annual Damaages in Thousands of Dollars Future With Existing Future Without Flood Year Slide 27

28 Output EAD Comparison By Year Expected Annual Damaages in Thousands of Dollars Future With Existing Future Without Flood Year Slide 28

29 Output EAD Comparison Expected Annual Damaages in Thousands of Dollars Historic Trends Future With Existing Future Without Flood Year Slide 29

30 James River FS/EIS Questions? Courtesy SD USGS Slide 30