Klamath Basin Water Distribution Model Workshop

OUTLINE Brief Description of Water Distribution Models Model Setups Examples of networks and inputs Demand Estimates and Checks Two Simple Modeling Examples The Klamath Basin Question and Answers

What is a water distribution model? A water accounting system. Routes water within a distribution network (stream, canal, etc.) to demands based on priority and supply. Brief Description of Water Distribution Models

River Demand 1, 1967 priority Basin Boundary Demand 2, 1905 priority Basin Outlet Demand 3, 1865 priority Demands #1 and #2 normally would not compete for water because they are on different tributaries. However, due to the existence of a downstream demand (#3) with a senior priority date, there is an interaction between demands #1 and #2.

Model Setups Network Examples and Data Requirements

Network Examples General Network Description The Ideal Network The Workable Network The Common Network

General Network Description Links represent tributaries or streams Source (inflow) nodes represent flows at tributary confluence Physical length of links are unimportant. Monthly time step eliminates need to calculate travel times. Relative placement of source nodes, demands and tributary confluence are important.

Unknown Parameters Physical River Demand 1 Basin Boundary Schematic River Source 1 Source 3 Source 2 Demand 1 Demand 2 Source 1 Source 2 Source 3 Net Demand 1 Net Demand 2 Basin Outflow Demand 2 Basin Outlet Basin Outflow 3 Types Sources (Inflows) Net Demands Outflows In aggregated terms, if any two parameters are known the third can be determine. General Network Description Tributary 1 Tributary 2 Tributary 3

The Ideal Network All demands, inflows and outflows within the basin are measured. No estimates required.

River Flow AccountingPhysical River Gage Demand 1 Demand 2 Basin Boundary Schematic Source 1 Source 3 Source 2 Demand 1 Demand 2 Source 1 + Source 2 + Source 3 - Demand 1 - Demand 2  Gage Record Because of return flows, Sources -Demands  Gage Flows Return flows can be directly calculated. Sources - Gage Record = Net Demands Demands -Net Demands = Return Flows The Ideal Network

The Workable Network. Two out of three parameters are known. inflows and outflows, or inflows and demands, or outflows and demands. Other parameter can be calculated directly.

Physical River Gage Demand 1 Demand 2 Basin Boundary Schematic River Source 1 Source 3 Source 2 Demand 1 Demand 2 Source 1 + Source 2 + Source 3 - Net Demand 1 - Net Demand 2 = Gage Record Calculated Net Demands directly (in aggregate terms) Flow Accounting Source Flows - Outflows = Net Demands The Workable Network

Project Areas 1 and 2 are similar to the “workable network”. Net demands are calculated from gage records of inflows and outflows from the project.

The Common Network. Only one out of three parameters are known. (Usually sub-basin outflow). Requires estimation of one of the unknown parameters.

Physical River Gage Demand 1 Demand 2 Basin Boundary Schematic River Source 1 Source 3 Source 2 Demand 1 Demand 2 Source 1 + Source 2 + Source 3 - Net Demand 1 - Net Demand 2 = Gage Record Flow Accounting Gage Record + Net Demands = Source Flows (Zero Demand Flow) The Common Network Need to estimate either source flows or net demands. Due to data limitations and time constraints, net demands were estimated in most areas above Klamath lake instead of source flows. Source flows can then be calculated according to the formula below.

Physical River Gage Demand 1 Demand 2 Basin Boundary Schematic River Source Flow Net Demands Flow Accounting Gage Record + Net Demands = Source Flow OR Zero Demand Flow The Common Network Aggregated This estimation of net demands and consequent calculation of source flows does not allow the modeling of the individual tributaries and demands. The demands and tributaries are aggregated.

Network Example Summary The Ideal Network - No estimates required Gage data used directly to determine demands and flows. The Workable Network - Net Demands are directly calculated. Demands may be Aggregated. The Common Network - Estimates of either source flows or net demands are required. Demands and source flows are aggregated.

Demands Estimates: How are net demands estimated? Checks

Net Demand = (Evapotranspiration - Precipitation - Soil Moisture) x Acreage Evapotranspiration estimated from Temperature Records using Hargreaves Equation. Precipitation taken from Rain Gage Data Soil Moisture estimated using Soil Conservation Service Surveys, and Antecedent Precipitation Crop Acreage

Example: Monthly Net Demand = (Evapotranspiration - Precipitation - Soil Moisture) x Acreage Monthly Net Demand = (7 inches inches inches) * 1000 acres = 500 ac-ft or 8.1 cfs

Demand Estimates Checks Diversions Simulated versus Measured Canal Data Depleted Flow Data Annual Net Demand Estimates Simulated versus Measured Average Yearly Trends Annual Crop ET Simulated versus “Agrimet” Data

Diversions Simulated versus Measured Canal Data Modoc Diversion Canal: Comparison of simulated monthly average versus miscellaneous daily measurements.

Diversions Simulated versus Measured Depleted Flows Wood River 91-93: Inflows from tributaries calculated from miscellaneous records. Demands estimated using previously described method. Outflows taken from BOR gage data.

Physical River Gage Demand 1 Demand 2 Basin Boundary Schematic Source 1 Source 3 Source 2 Demand 1 Demand 2 Source 1 + Source 2 + Source 3 - Net Demand 1 - Net Demand 2 = Outflows Flow Accounting Compare Simulated Outflow to Gage data to check estimates

Diversion Check Simulated diversions appear to be reasonable when compared to measured canal and depleted flow data.

Annual Net Demand Estimates Simulated average annual demand above Klamath Lake versus measured average annual demand in the Project. Climate is similar. Same basin. Demand is normalized by acreage (ac-ft/ac).

Annual Net Demand Estimates Check Estimated annual demands above Klamath Lake appear reasonable when compared to measured data available elsewhere in the basin. Yearly simulated variations in annual demands generally follow measured data.

Annual Crop ET Simulated annual crop ET versus “Agrimet” data in Lakeview.

Model Examples Integrating Instream Demands Single Tributary System Two Tributary System

Actual River Demand 1 Demand 2 Basin Boundary Schematic River Zero Demand Flows Demand A Flow Accounting ZDF -Instream Demands = Flows Available for Irrigation Demands Instream Demand Instream Demands

Demand A, 1864 Instream Demand C ZDF Tributary A ZDF Tributary B Instream Demand D Demand B, 1905 Instream demand D has a call on upstream demands. However, the shortages appear in Demand A instead of Demand B even through Demand A has a senior priority date. The reason is that instream demand C is effectively causing the shortages to Demand A, which consequently increases flows to instream demand D. Thus demand B is not called to reduce its use. Counterintuitive Demand Interaction.

Klamath Basin Setup

Spencer Creek Lake Ewauna Project Area A2 Other Tributaries Seeps and Springs Wood River and Tributaries Accretions Middle Sprague ZDF Sycan Accretions Middle Williamson ZDF Lower Williamson Klamath Straits Drain ZDF Upper Williamson LEGEND Channels Source Nodes Consumptive Uses Junctions Marshes/Lakes GAUGE OVERLAP PERIOD (73-97) Project Area A1 ZDF Sprague LRDC Ewauna Accretions