Rio Grande Basin Hydroeconomic Model a.k.a. Bucket Model

Current Version: 2018/02/25
Source Code: Github Page Here
Modeling Software: The General Algebraic Modeling Software (GAMS)


The “Bucket Model” is a simple coarse-scale basin model that simulates all major water sources, sinks, uses, and losses as well as economic values of water as well as institutional constraints governing water supply and use for the Middle Rio Grande between the inflow to Elephant Butte Reservoir and Fort Quitman on the Rio Grande. This model is designed to be a useful tool for improving our understanding of the hydrology, agronomy, institutions, and economics to guide analysis of policy and management questions that are important to stakeholders.

The current version of the model is a simple “three bucket” model that reflects water storage, inflow, and outflow for project storage and for the region’s two major aquifers, the Mesilla and Hueco. In this version, the three water users are irrigated agriculture, urban demands, and environmental / recreational demands for water volumes in surface storage. For aquifers, the major uses are agriculture and urban use. Existing as well as potential water use is predicted as a constrained optimization model that identifies water use and flow patterns that maximize discounted net present value of water by adjusting water use patterns in the river-reservoir-aquifer system for the model’s time horizon.

Required inputs include hydrologic data such as surface inflows to storage, crop water requirements by crop, surface treaty delivery requirements from the U.S. to Mexico, evaporation rates from surface reservoir storage, and reservoir capacity. Water use demand data include crop yields, costs of production, crop price, price elasticity of demand, and urban population.

Model outputs include total farm income, recreation economic benefits, total urban net benefits, reservoir releases, surface storage volume, groundwater pumping and recharge, 1906 Treaty deliveries by the U.S. to Mexico, reservoir surface evaporation, total water use, and the discounted net present value of total economic benefits and its distribution among major water users.


Ward et. al., 2019
The economics of aquifer protection plans under climate water stress: New insights from hydroeconomic modeling.
Journal of Hydrology, Volume 576, September 2019, Pages 667-684

Model Composition

Flow nodes

  • 5 river gauge nodes
  • 1 streamgauge inflow node San Marcial above Elephant Butte
  • 5 watershed point inflow nodes from ungauged precip into river reaches
  • 5 diversion nodes
  • 5 consumptive use nodes
  • 5 surface water return flow nodes
  • 2 groundwater pumping nodes
  • 1 reservoir storage release node

Stock nodes

  • 1 reservoir node
  • 2 aquifer nodes


Set Set Elements Set Description Elements Description
Flows i Location of important nodes in middle RG basin--Elephant Butte to MX. Marcial_h_f Headwater flow nodes
Wshed_1_h_f Headwater flow nodes
RG_Caballo_out_v_f RGR project storage outflow gauge on Rio Grande
RG_El_Paso_v_f New Mexico Texas State Line on Rio Grande
RG_above_MX_v_f Rio Grande above Mexico diversion
RG_below_EPID_v_f Gauge below El Paso irrigation diversion use on river
EBID_d_f Divertion nodes
LCMI_d_f Divertion nodes
EPMI_d_f Divertion nodes
MXID_d_f Divertion nodes
EPID_d_f Divertion nodes
EBID_u_f Consumptive use flow nodes
LCMI_u_f Consumptive use flow nodes
EPMI_u_f Consumptive use flow nodes
MXID_u_f Consumptive use flow nodes
EPID_u_f Consumptive use flow nodes
EBID_rr_f River return flow nodes
LCMI_rr_f River return flow nodes
EPMI_rr_f River return flow nodes
MXID_rr_f River return flow nodes
EPID_rr_f River return flow nodes
EBID_ra_f Aquifer return flow nodes
LCMI_ra_f Aquifer return flow nodes
EPMI_ra_f Aquifer return flow nodes
MX_ra_f Aquifer return flow nodes
EPID_ra_f Aquifer return flow nodes
Store_rel_f Res storage-to-river release node (outflow - inflow)
Stocks u Location of key water storage elements Storage_res_s Caballo/Elephant Butte reservoir location
Mesilla_aqf_s Mesilla Aquifer Location
Hueco_aqf_s Hueco Bolson location
Crop j crop pecans Pecan orchards
veges Veges (chile, onions, lettuce, etc..)
forage Cattle feed
Technology k irrigation technology flood Flood irrigation technology
Time t years tfirst Starting year
tmid Middle years
tlast Terminal year
tlater All years after initial
Policy p Policy scenarios (historical or user changeable) 1-policy_hist Historical policy: historical starting surface storage volume all years
2-policy_base Base policy: historical starting surface volume in year 1 (1996)
3-policy_new New policy: 10% reduced starting surface storage volume year 1 (1996)
Water Supply w Supply scenarios (climate, water import, etc) 1-w_supl_base Historical inflows at San Marcial Gauge (1996-2015)
2-w_supl_new New inflow scenario, 10% reduced inflows at San Marcial Gauge (1996-2015)

Input Parameters

List of input parameters available on the user interface:

Parameter Label Description Units
Yield_p Observed Crop Yield Measurement of the amount of a crop that was harvested per unit of land area. tons/ac
Price_p Observed Crop Prices Observed crop prices USD/ton
Bau_p Observed Irrigation Water Depth Water per acre of various dimensions ft
lan_p Observed Land in production Land in production over all observed historical years 1000ac
Cost_p Crop Production Costs Crop production costs per acre USD/ac
ag_gw_pump_capacity_p Agricultural pumping capacity Agricultural pumping capacity in acre feet per year by aquifer AF/yr
ag_av_gw_cost_p Agricultural Average Costs of Pumping Ground Water Average irrigation costs of pumping ground water ($ per a-f) USD/AF
Netrev_acre_p Net Farm Income per Acre Net revenue per acre observed in base year price x yield - cost ($ per acre) USD/AC
elast_p Urban Price Elasticity of Demand A measure of the relationship between a change in the quantity of water demanded and a change in its price N/A
urb_price_p Observed Historical Urban Price of Water Observed historical urban price of water $1000/1000AF
urb_use_p Observed Historical Urban Water Deliveries Observed historical urban water deliveries 1000AF/yr
urb_Av_cost0_p Urban Cost of Supply Urban cost of supply per unit delivered to the home USD/AF
urb_cost_grow_p Urban Average Cost Growth Rate Urban average cost growth rate prop/yr
pop0_p Initial Number of Urban Water Buying Households Initial number of urban water buying households 1000
urb_gw_cost_grow_p Urban Average Pumping Cost Growth Rate Urban average pumping cost growth rate prop
rho_pop_p Urban Water Buying Households Growth Rate Urban water buying households growth rate prop/yr
urb_av_gw_cost0_p Urban Average Pumping Cost Average cost of urban aquifer pumping excluding treatment 1000USD
urb_gw_pump_capacity_p Urban Pumping Capacity Urban pumping capacity KAF/yr
pop_p Urban Water Buying Households By Year Number of urban households hooked up to water utility 1000
urb_av_cost_p Urban Average Cost in Future by Year Predicted average total cost of supplying urban water 1000USD
urb_av_gw_cost_p Urban Average Groundwater Pump Cost by Year Predicted average groundwater pumping costs for urban use 1000USD
us_mx_1906_p Observed US-Mexico 1906 Treaty Flows at Acequia Madre Observed US-Mexico 1906 treaty flows at Acequia Madre 1000AF/yr
tx_proj_op_p TX proportion of SAN MARCIAL FLOWS Texas proportion of San Marcial Flows according to the 2008 Project Operating Agreement prop
sw_sustain_p Ending Proportion of Starting Surface Water Storage Ending proportion of starting surface water storage prop
gw_sustain_p Ending Proportion of Starting Ground Water Storage Ending proportion of starting ground water storage prop
Bmda_p Urban Return to the Aquifer as a Proportion of Divert Urban return to the aquifer as a proportion of divert prop
Bmxda_p MX Return to the Aquifer System as a Proportion of MX Diversions MX return to the aquifer system as a proportion of MX diversions prop
sourc_p Annual Water Inflows at San Marcial Gauge Annual water inflows at San Marcial gauge 1000AF/yr
gaugeflow_p Annual Gauged Streamflows Annual gauged streamflows at selected gauges 1000AF/yr
z0_p Initial Project Storage Level Initial reservoir levels at reservoir stock nodes 1000AF
zmax_p Reservoir Storage Capacity Maximum reservoir storage capacity 1000AF
z_p Rio Grande Project Storage by Year Rio Grande Project Storage by year (EB + Caballo) 1000AF
residdd_p Observed Predicted Storage by Year Observed Predicted Storage by year 1000AF
depth0_p Initial Aquifer Level by Aquifer Aquifer starting storage level 1000AF
qmax_p Aquifer Storage Capacity Aquifer maximum storage capacity 1000AF
aq_area_p Land Area Overlying Aquifer Land area overlying aquifer 1000ac
recharge_p Annual Mountain Front Aquifer Recharge Annual mountain front aquifer recharge 1000AF/yr
porosity_p Average Aquifer Porosity Average aquifer porosity N/A
precip_rat_p Reservoir Precipitation Rate Feet gained per exposed acre per year ft/yr
Evap_rate_p Reservoir evaporation rate Feet lost per exposed acre ft/yr
LANDRHS_p Developed Land Area by Irrigation District Land available by irrigation district 1000ac
SW_Treat_capac_p Urban Surface water treatment capacity by city Urban Surface water treatment capacity by city 1000AF
Bag_pump_aqf_return_p Proportion of Agricultural Water Pumped Recharging Pumped Aquifer prop
urb_av_back_cost0_p Urban Backstop Technology Costs Urban backstop technology costs including treatment approximate cost of imported water as of 2017
urb_back_cost_grow_p Growth in Urban Backstop Technology Costs Growth in urban backstop technology costs proportion per year (May Fall) prop
urb_av_back_cost_p Future Urban Ave Backstop Technology Cost prop
Burb_back_aqf_rch_p Proportion of Urban Water from Backstop Technology Recharging Aquifer

Output Variables

Output variables included on interface as of version Beta 0.7:

Variable Label Description Units
evaporation Evaporation Volume Reservoir surface evaporation volume by year KAF/yr
B1_area_vol_p Impact of Changes in Volume on Changes in Area (acres per 1000 ac feet) Impact of changes in volume on changes in area (acres per 1000 ac feet)
Z0_p Initial Reservoir Levels at Reservoir Stock Nodes Initial reservoir levels at reservoir stock nodes KAF
water_flows Water Flows Water flows by period KAF/yr
water_stocks Water Stocks Reservoir water storage KAF/yr
wat_stock0_p Initial water stocks Initial water stocks
river_flows River Flows River flows KAF/yr
inflows_p Inflows by Period Water Inflows into system from various sources KAF/yr
diversions Water Diversions Water diversions KAF/yr
SWacres Surface Irrigated Land in Production Surface Irrigated land in production Kac/yr
GWacres Aquifer Irrigated Land in Production Aquifer irrigated land in production Kac/yr
surf_use Surface Water Use Surface water Use KAF/yr
r_return_o Return Flows from River to River Return flows from river to river KAF/yr
pop_p Urban Population by Year Urban population by year 1000s
price_p Crop Prices Crop prices $/ton
cost_p Crop Production Costs Crop production costs $/ac
netrev_acre_p Crop Net Revenue per Acre Crop net revenue per acre $/ac
land_p Land in Production in Acres Land in production in acres acres
yield_p Crop Yield Crop yield tons/ac
urb_price Urban Price Urban water price USD/AF
urb_con_surp Urban Consumer Surplus Difference between what customer is willing to pay to what he has to pay KUSD/yr
urb_use_p_cap Urban Use per Capita Total urban use divided by total customer households AF/Person
ag_value Agricultural Net Benefits by Crop Agricultural net economic value (total profitability) KUSD/yr
ag_ben Agricultural Benefits Net income over crops by farming region and year KUSD/yr
ag_m_value Agricultural Marginal Value of Water Farm price of water plus scarcity value USD/AF
yield Crop Yield Yield by crop and technology tons/ac
Ba_use_p Crop Water Consumption Depth (ET) Crop water consumption depth (ET) feet
urb_av_cost_p Future Urban Average Cost Future urban average cost $ / a-f
elast_p Urban Price Elasticity of Demand Urban price elasticity of demand
tx_proj_op_p Proportion of San Marcial Gauged Flows Going to NM-TX Stateline Proportion of San Marcial Gauged flows going to NM-TX stateline 0 - 1
ag_sw_use Agricultural Surface Water Use Agricultural Surface Water Use by period KAF/yr
urb_pump Urban Water Pumping Urban water pumping from aquifer KAF/yr
urb_sw_use Urban Surface Water Use Urban water use from surface water KAF/yr
recharge_p Annual Average Recharge KAF/yr
urb_revenue Urban Revenue Price per acre feet multiplied by quantity supplied by the urban supplier KUSD/yr
urb_gross_ben Urban Gross Economic Benefit Revenue plus consumer surplus KUSD/yr
urb_costs Urban Costs of Production Total cost of urban supplied water KUSD/yr
urb_value Urban Total Net Benefit Producer plus consumer surplus (urban gross benefits - cost of supply) KUSD/yr
urb_value_af Urban Net Value per Unit Water Urban economic benefits per acre foot USD/ac-ft
urb_use Urban Water Use Urban water use (surface diversions + pumping) KAF/yr
urb_m_value Urban Marginal Value Marginal net benefit (price - marginal cost) USD/ac-ft
zmax_p Maximum Reservoir Storage Capacity Maximum reservoir storage capacity KAF
surf_area Total Surface Area by Period Total surface area by period Kac/yr
env_ben Environmental Benefit from Flows Environmental benefits by year (willingness to pay for environmental flows) KUSD/yr
tot_ben Total Benefits Over Uses Sum of total benefits over region and uses KUSD/yr
dnpv_ben Discounted Net Present Value of Benefits Sum of total benefits over region, uses and time periods KUSD
us_mx_1906_p Actual Deliveries at Aceqia Madre Gauge at US-MX Border Actual deliveries at Aceqia Madre gauge at US-MX border KAF
sw_sustain_p Terminal Period Surface Water Sustainability Percentage Terminal period surface water sustainability percentage 0 - 1
gw_sustain_p Terminal Period Groundwater Sustainability Proportion Terminal period groundwater sustainability proportion 0 - 1
rec_ben Recreation Benefit Reservoir recreation benefits by year (willingness to pay for recreation values) KUSD/yr
tot_ag_pump Total Agricultural Pumping Total agricultural pumping summed over crops and technology KAF/yr
gw_stocks Groundwater Aquifer Stocks Groundwater aquifer stocks by period KAF/yr
gw_stocks0_p Groundwater Aquifer Starting Stocks Groundwater aquifer starting stocks KAF
urb_gw_pump_capacity_p Pumping Capacity by Urban Area Pumping capacity by urban area KAF/yr
qmax_p Maximum Aquifer Storage Capacity Maximum aquifer storage capacity KAF
urb_av_gw_cost_p Future Urban Average Groundwater Pumping Costs Future urban average groundwater pumping costs $/a-f
ag_av_gw_cost_p Future Agricultural Average Groundwater Pumping Costs Future agricultural average groundwater pumping costs KAF/yr
urb_gw_pump_capacity_p Maximum Urban Groundwater Pumping Capacity Maximum urban groundwater pumping capacity KAF/yr
ag_gw_pump_capacity_p Maximum Agricultural Groundwater Pumping Capacity Maximum agricultural groundwater pumping capacity KAF/yr
landrhs_p Upper Bound on Developed Irrigated Land Upper bound on developed irrigated land acres
aquifer_depth Groundwater Aquifer Depth Groundwater aquifer depth ft/yr
porosity_p Average Porosity of Each Aquifer (Proportion That Holds Water) 0 - 1
qmax_p Maximum Aquifer Storage Capacity KAF
q0_p Starting Aquifer Storage Level KAF
aq_area_p Plan View Aquifer Area 1000 acres
a_return_o Agricultural Return Flows from River to Aquifer Surface return flow from agricultural river diversions that return to the aquifer KAF/yr
ag_pump_aq_rch Agricultural Return from Pumping to Aquifer Agricultural pumping that contributes to aquifer recharge KAF/yr
z_p Rio Grande Project Surface Storage by Year Rio Grande Project Surface Storage by year KAF
xv_lb_p Lower Bound Proportion on Stream Gauge Flows Compared to History Lower bound proportion on stream gauge flows compared to history 0 - 1
xv_ub_p Upper Bound Proportion on Stream Gauge Flows Compared to History Upper bound proportion on stream gauge flows compared to history 0 - 1
gaugeflow_p Annual Historical Gauged Stream Flows Annual historical gauged stream flows KAF/yr
model_resid_p Model Residual Compared to Predicted Flows (Not Used) Model residual compared to predicted flows (not used)
precip Total Precipitation by Period Total precipitation by period KAF/yr
residdd_p Residual from Observed Storage Residual from observed storage
tacres Total Acreage by Crop Total irrigated land in production summmed over crops and technologies Kac/yr
tswacres Total Surface Water Acreage Total surface water acreage Kac/yr
tgwacres Total Ground Water Acreage Total ground water acreage Kac/yr
ttacres Total Acreage Sum of SW and GW acreage Kac/yr
precip_rate_p Precipitation Rate by Year Precipitation rate by year ft/yr
source_p Annual Basin Inflows at Headwaters From Precipitation Annual basin inflows at headwaters from precipitation ft/yr
rho_pop_p Urban Population Growth Rate per Year Urban population growth rate per year 0 - 1
urb_back_use Urban Backstop Technology Use Urban water use from backstop technology KAF/yr
urb_back_aq_rch Urban Return to Aquifer from Backstop Tech Recharging Aquifer Urban water use from backstop technology recharging the aquifer K AF/yr
total_ag_ben Total Agricultural Benefits Total agricultural benefits 1000 USD
avginflows Average Total Inflows Total inflow average, excluding first year KAF/yr
avgstocks Average Reservoir Storage Average project storage over selected period KAF/yr
tot_inflows_p Total Inflows Over Nodes by Period KAF/yr
avgwaterflows Unknown to FAW
avgwaterdeliveries Rio Grande Project Surface Deliveries Average surface deliveries excluding first year over selected period KAF/yr
tot_rg_deliveries Unknown to FAW
avgswdivertions Basin Surface Water Diversions Average surface water diversions excluding first year over selected period KAF/yr
avgswuse Total Basin Surface Water Use Average surface water use excluding first year over selected period KAF/yr
tot_swuse Unknown to FAW
avgriverflow Basin Surface Flows Average surface flows over selected period KAF/yr
avgagpumping Agricultural Ground Water Pumping Average agricultural water pumping excluding first year over selected period KAF/yr
avgurbpumping Urban Groundwater Pumping Average urban water pumping excluding first year over selected period KAF/yr
avgurbbackuse Urban Substitute Technology Use Average urban water backstop technology use over selected period KAF/yr
avgmxflows US-Mexico Treaty Deliveries Average US-MX treaty delivery flows excluding first year over selected period KAF/yr
mx_flows US Mexico 1906 Treaty Flows KAF/yr
total_ag_ben Total Agricultural Benefits Total Agricultural Benefits KUSD
avgtotagben Agricultural Economic Benefits Average agricultural economic benefits excluding first year over selected period KUSD
avgtoturbben Urban Economic Benefits Average urban economic benefits excluding first year over selected period KUSD
avgenvben Environmental River Benefits Average environmental benefits KUSD
avgrecben Reservoir Recreation Economic Benefits Average reservoir recreation economic benefits over selected period KUSD
avgtotben Total Economic Benefits Average annual economic benefits over selected period KUSD


Frank A. Ward
Dept of Agr Economics/Agr Business
New Mexico State University, Las Cruces, NM USA

Alex Mayer
Michigan Technical University

Sponsored by US Dept of Agriculture: 5 yr project 2015 - 2020