21 st Century Management Solutions for Water Supply and Demand

Transcription

1 21 st Century Management Solutions for Water Supply and Demand AWRA Annual Conference November 9, 2017 Bill Szafranski Roger Wolvington

2 Abstract Water supply planning in the Western US is critical for managing limited resources Conventional approaches such as using spreadsheets are being abandoned for more modern modeling approaches We will discuss these modern approaches centered around our model CRAM

3 Water Allocation Models These models need to meet the following requirements: A good user interface Perform rapid calculations Represent real-life features (reservoirs, inflows, demands, etc.) Optimize a system Preserve mass balance Provide insights for analysts, water managers, utilities, planners, etc.

4 What Can They Do? Applications Long term supply planning Demand build-out Firm yield analysis What if scenario analysis Drought, climate change, new capital improvement projects

5 A Few Models OASIS HydroLogics model Uses linear programming MODSIM CSU model run by John Labadie RELAX flow optimization algorithm PACSIM Platte and Colorado Simulation Model Model owned by and run internally by Denver Water (FORTRAN) StateMod Colorado s large basin water rights modeling system CalSim or WRIMS California s State Water Project/ Central Valley Project simulation model Uses linear programming CRAM Lynker Technologies model Out of Kilter network optimization algorithm

6 CRAM Central Resources Allocation Model

7 Storage (AF) Case Studies 1. Bosque del Apache Decision Support Tool (BdADST) Managing water rights for the US Fish and Wildlife Service Used at the Bosque del Apache National Wildlife Refuge 2. Llandegfedd Reservoir Operations Model Optimization of a reservoir guide curve Source: US Fish and Wildlife Reservoir Guide Curves Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

8 Case Study 1 Bosque del Apache Background Bosque del Apache National Wildlife Refuge in New Mexico serves as habitat for migratory birds 57,000 acres of land (89 mi 2 ) includes wetlands, crops and riparian forests Rio Grande passes through the Refuge

9 Bosque del Apache Purpose US Fish and Wildlife needed a better way to administer their water rights. 1. Decision support tool for annual water planning 2. Scenario analysis for droughts 3. Prove and quantify historical water use 4. Minimize groundwater use in Refuge

10 Bosque del Apache CRAM Modeling Outline Build System Model (CRAM) Run Annual Planning Scenarios Run Drought Simulations

11 Bosque del Apache Build model to System Specifications In order to maintain habitat, the refuge manages irrigation water through a complex system that includes return flows and wells 4 surface sources 12 supplemental wells 123 management units (MU) 32 miles of canals Bosque del Apache CRAM setup

12 Bosque del Apache Scenario Analysis 1. Annual Water Planning (Demand Driven Analysis) Specify land use type for 123 MUs for each month of the year Ponded, small grains, corn/alfalfa, fallow, etc. Specify GW pumping Run Model Output: Solve for water used (water required) Month Land Use Consumptive Irrigation Use (ft.) Diversion (AF) Jan Fallow Feb Fallow Mar Corn/Alfalfa Apr Corn/Alfalfa May Corn/Alfalfa Jun Corn/Alfalfa Jul Corn/Alfalfa Aug Corn/Alfalfa Delete farm field diversion Sep Corn/Alfalfa Oct Corn/Alfalfa Nov Fallow Dec Fallow Month Land Use Consumptive Irrigation Use (ft.) Diversion (AF) Jan Open Water/Flow Through Feb Open Water/Flow Through Mar Open Water/Flow Through Apr Open Water/Flow Through May Open Water/Flow Through Jun Fallow Jul Fallow Aug Fallow Sep Fallow Oct Fallow Nov Open Water/Flow Through Dec Open Water/Flow Through

13 Bosque del Apache Scenario Analysis 1. Annual Water Planning (Demand Driven Analysis)

14 Bosque del Apache Scenario Analysis 1. Annual Water Planning (Demand Driven Analysis)

15 Bosque del Apache Scenario Analysis 2. Drought Analysis (Supply Driven Analysis) Purpose: Used to determine MU performance during years of low inflow. Specify inflows to Refuge Specify monthly GW pumping rates Specify land use/operations settings for the 123 MUs Output: Analyze water shortages for MUs by month

16 Bosque del Apache Scenario Analysis 2. Drought Analysis GIS output of MUs Shortages for 1 month by MU

17 Case Study 2: Llandegfedd Reservoir Problem How can we change operations at a pumped reservoir to improve the river environmental flows without impacting municipal water supply (reliability)

18 Case Study 2: Llandegfedd Reservoir Approach: 2-Part Solution 1. River simulation: Synthetic daily streamflow to increase limited historical dataset 2. Reservoir rules optimization and simulation model: CRAM simulated reservoir operating rules, inflows and demands to determine supply reliability

19 River Simulation Synthetic Flow Data Empirical resampling (K-Nearest Neighbor) 500 simulations of 39 years at a daily time step = 19,500 years Simulated inflows represented the statistics of original 39-year daily dataset well (mean, variance, skew) Simulated Flow Demand Data Demand data was paired with its corresponding flow from the original 39- year dataset

20 Reservoir Simulation CRAM Modeling Outline Step 1 Build System Model (CRAM) Step 2 Optimize Reservoir Operating Rules (GA-CRAM) Step 3 Evaluate Proposed Operations Evaluate Optimized Operations (GA-CRAM)

21 System Model (CRAM) Step 1:

22 Storage (AF) Reservoir Simulation Step 2: Optimization (GA-CRAM) Use Excel s built-in genetic algorithm to determine best reservoir guide curve (set of reservoir pool elevations) Constraints Min & max monthly pool elevations Max abstraction from river Given Values Set of inflows Set of demands Solve Choose reservoir targets (pool elevation) Calculate total shortage (demand-supply) Objective function: Minimize shortages Reservoir Storage Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High Storage Target Storage Low Storage Maximum Contents

23 Reservoir Simulation Optimization Detail (GA-CRAM) Population size 50 Mutation rate of Model tested 4,881 solutions End of simulation due to lack of improvement: 25 hours Total Simulation Time: 29 hours End of Model Run: Solver cannot improve current solution. All constraints are satisfied.

24 Reservoir Simulation Step 3: Evaluate Operations 1. Run Proposed Reservoir Operations a. 39-years of historical inflow/demand data b. 19,500-years of simulated inflow/demand data 2. Run GA-CRAM Created (Optimized) Reservoir Operations a. 39-years of historical inflow/demand data b. 19,500-years of simulated inflow/demand data

25 Reservoir Simulation Results: GA-CRAM Operations (19,500-year simulation) Max storage 1% occurrence Dead storage

26 Reservoir Simulation Results: Proposed Operations (19,500-year simulation) Max storage 1% occurrence Dead storage

27 Reservoir Simulation River Analysis No change in river 20 th percentile Client Proposed Low flow months GA-CRAM

28 Summary Water allocation models provide superior capabilities for tracking and analyzing water supply and demand within a system. They allow fast scenario analysis to help answer management questions.

29 CRAM Web Tool Visit the CRAM Interactive Tool here:

30 CRAM Web Tool Visit the CRAM Interactive Tool here: