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

Current Version: 2019/21/01
Source Code: Github Repository
Modeling Software: The General Algebraic Modeling Software (GAMS)

Introduction

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
https://doi.org/10.1016/j.jhydrol.2019.06.081

Townsend, N. T.; and Gutzler, D. S., 2020
Adaptation of Climate Model Projections of Streamflow to Account for Upstream Anthropogenic Impairments.
JAWRA Journal of the American Water Resources Association
https://doi.org/10.1111/1752-1688.12851

Torell, G. L., Lee, K. D., Garnica, L. A., Mayer, A. S., & Ward, F. A. 2022.
Least-Cost Provision of Ecosystem Services from Water: When, Where, and How Much? Journal of Water Resources Planning and Management, 148(2),
https://doi.org/10.1061/(ASCE)WR.1943-5452.0001511

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

Sets

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 from the model that are available on the user interface:

Parameter	Label	Description	Units
Yield_p	Observed Crop Yield	Average harvest of representative crops	Tonnes per Acre
Price_p	Observed Crop Prices	Observed crop prices per ton in historical period	US Dollars per Ton
lan_p	Observed Land in production	Land in production over all observed historical years	Thousands of Acres
Cost_p	Crop Production Costs	Crop production costs per acre	US Dollars per Acre
ag_gw_pump_capacity_p	Agricultural pumping capacity	Agricultural pumping capacity in acre feet per year by aquifer	Acre-Feet
ag_av_gw_cost_p	Agricultural Average Costs of Pumping Ground Water	Irrigation groundwater pumping costs averaged over all crops	US Dollars per Acre-Foot
ag_back_cost_grow_p	Change in Agricultural Substitute Technology Costs	The cost of agricultural substitute technologies, such as water imports	percent
ag_av_back_cost0_p	Agricultural Substitute Technology Costs	Initial cost of agricultural substitute technology such as water imports	US Dollars per Acre-Foot
elas_p	Water 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	Urban Price of Water	Observed prices of water in historical period	US Dollars per Acre-Foot
urb_use_p	Urban Water Deliveries	Observed historical urban water deliveries	Thousands of Acre-Feet
urb_Av_cost0_p	Urban Cost of Supply	Cost to urban water utilities to supply water to homes	US Dollars per Acre-Foot
urb_cost_grow_p	Urban Average Cost Growth Rate	Average annual rate of increase in cost of water per acre foot for urban use	percent
pop0_p	Initial Number of Urban Water Buying Households	Initial number of urban water buying households from 1994	Thousands
urb_gw_cost_grow_p	Urban Average Pumping Cost Growth Rate	Average annual increase rate in the cost of pumping for urban water use	percent
rho_pop_p	Urban Water Buying Households Growth Rate	Percentage growth per year of urban water users as households	percent
urb_av_gw_cost0_p	Urban Average Pumping Cost	Average cost of urban aquifer pumping excluding treatment	Thousands of US Dollars
urb_gw_pump_capacity_p	Urban Pumping Capacity	Annual urban pumping capacity	Thousands of Acre-Feet
us_mx_1906_p	Observed US-Mexico 1906 Treaty Flows at Acequia Madre	Observed US-Mexico 1906 annual treaty flows at Acequia Madre during period of 1994-2015	Thousands of Acre-Feet
tx_proj_op_p	Texas proportion of San Marcial Flows	Proportion of San Marcial Flows Texas receives according to the 2008 Project Operating Agreement	proportion
sw_sustain_p	Ending Proportion of Starting Surface Water Storage	A lower bound for the amount of water held in the reservoir at the end of the model as a percentage of starting year value (1994)	percent
gw_sustain_p	Ending Proportion of Starting Groundwater Storage	Lower bound for the amount of water in the aquifer at the end of the model run as a percentage of the amount at starting year (1994)	percent
source_p	Annual Water Inflows at Different Location Points	Annual water inflows over different locations and scenerios across the Rio Grande	Thousands of Acre-Feet
san_mar_in	Annual Water Inflows at San Marcial Gauge	Annual water inflows coming through the San Marcial twin gauges and into Elephant Butte reservoir	Thousands of Acre-Feet
gaugeflow_p	Annual Gauged Streamflows	Annual gauged streamflows at selected gauges	Thousands of Acre-Feet
z0_p	Initial Reservoir Storage Level	Starting reservoir storage volume combining Elephant Butte and Caballo reservoir	Thousands of Acre-Feet
zmax_p	Reservoir Storage Capacity	Maximum reservoir storage capacity in thousands of acre feet	Thousands of Acre-Feet
z_p	Rio Grande Project Storage by Year	Rio Grande Project storage by year (Elephant Butte and Caballo)	Thousands of Acre-Feet
depth0_p	Starting Depth	Starting aquifer depth in feet	Feet
qmax_p	Aquifer Storage Capacity	Storage capacity by aquifer (assumed boundaries)	Thousands of Acre-Feet
aq_area_p	Land Area Overlying Aquifer	Land area overlying aquifer in thousands of acres	Thousands of Acres
recharge_p	Annual Mountain Front Aquifer Recharge	Amount of recharge expected from mountain front watersheds	Thousands of Acre-Feet
porosity_p	Average Aquifer Porosity	Porosity relates to the amount and type of holes in the soil that allow water to drain to the aquifer	N/A
precip_rat_p	Reservoir Precipitation Rate	Reservoir precipitation rate - feet gained per exposed acre per year	Feet
evap_rate_p	Reservoir evaporation rate	Reservoir evaporation rate - feet lost per exposed acre per year	Feet
LANDRHS_p	Developed Land Area by ID	Developed land area per irrigation district in thousands of acre feet	Thousands of Acres
SW_Treat_capac_p	Urban Surface Water Treatment Capacity	Urban surface water treatment capacity by city	Thousands of Acre-Feet
Bag_pump_aqf_return_p	Recharge from Agricultural Pumped Water	Proportion of agricultural water pumped from an aquifer which might recharge the aquifer from which it was pumped	percent
urb_av_back_cost0_p	Urban Substitute Technology Costs	Initial cost of urban substitute technology (such as desalination), including treatment of imported water.	US Dollars per Acre-Foot
urb_back_cost_grow_p	Change in Urban Substitute Technology Costs	The cost of urban substitute technologies, such as desalination, may increase or decrease over time	percent
Burb_back_aqf_rch_p	Recharge from Urban Substitute Technologies	Proportion of urban water from substitute technology which might recharge an aquifer	proportion
tStartOffset	Offset years after initial	Change of initial year to initial plus value of offset	N/A
tElements	Total Number of Year Elements	Total number of years after initial	N/A
chooser	Policy Scenario Selector	Bucket model index for switching between policy scenarios	N/A

Output Variables

List of output variables from the model that are available on the SWIM interface:

Variable	Label	Description	Units
evaporation	Evaporation Volume	Estimated volume of water loss due to evaporation over reservoir surface area per year	Thousands of Acre-Feet
water_flows	Water Flows	Yearly water flows of various kinds: diversions, returns, and use at a particular point (used for water accounting)	Thousands of Acre-Feet
water_stocks	Surface Water Storage	Average volume of water stored at Elephant Butte and Caballo reservoirs in a given year	Thousands of Acre-Feet
river_flows	River Flows	Estimated volume of river water in a given year that flowed passed a specific location in the region	Thousands of Acre-Feet
diversions	Water Diversions	Extraction of water away from surface or groundwater sources	Thousands of Acre-Feet
SWacres	Surface Irrigated Land in Production	Surface land area used for agricultural crop production that uses water from surface reservoir storage	Thousands of Acres
GWacres	Aquifer Irrigated Land in Production	Crop producing land for which majority of water is supplied by pumped water	Thousands of Acres
surf_use	Surface Water Use	Effective amount of water consumed by cities and irrigation districts that was sourced surface sources	Thousands of Acre-Feet
r_return_o	Return Flows from River to River	Residual water that was diverted from the river for consumptive use and is returned back to the river stream	Thousands of Acre-Feet
urb_price	Urban Price	Charge for urban water use per acre foot	US Dollars per Acre-Foot
urb_con_surp	Urban Consumer Surplus	Difference between what urban household cutomers are willing to pay to what they are charged in their water bills	Thousands of US Dollars
urb_use_p_cap	Urban Use per Household	Total urban water consumption divided by total number of households	Acre-Feet
ag_value	Agricultural Net Benefits by Crop	Total economic profits generated over the projection period from each type of crop per irrigation district in the region	Thousands of US Dollars
ag_ben	Farm Income	Total agriculture profits generated by irrigation districts each year	Thousands of US Dollars
ag_m_value	Agricultural Marginal Value of Water	The increased amount of economic value that an additional acre-foot of water provides in the agricultural sector	US Dollars per Acre-Foot
yield	Crop Yield	Crop yield in tons per acre	Tonnes per Acre
ag_sw_use	Agricultural Surface Water Use	Effective volume of surface water diverted from the Rio Grande used for crop irrigation in each irrigation district per year	Thousands of Acres
urb_pump	Urban Water Pumping	Annual volume of water for urban use sourced from underlying aquifers	Thousands of Acre-Feet
urb_sw_use	Urban Surface Water Use	Effective volume of water consumed in the urban sector sourced from surface water	Thousands of Acre-Feet
urb_revenue	Urban Revenue	Revenue generated by local water utility supplier	Thousands of US Dollars
urb_gross_ben	Urban Gross Economic Benefit	Revenue from urban water bills	Thousands of US Dollars
urb_costs	Urban Costs of Production	Cost of delivering water for consumption in urban households	Thousands of US Dollars
urb_value	Urban Total Net Benefit	Total net economic benefits generated by the urban sector water use	Thousands of US Dollars
urb_value_af	Urban Net Value per Unit Water	Economic value of each acre-foot of water	US Dollars per Acre-Foot
urb_use	Urban Water Use	Total volume of water effectively consumed by the urban sector	Thousands of Acre-Feet
urb_m_value	Urban Marginal Value	The increased amount of economic value that an additional acre-foot of water provides in the urban sector	US Dollars per Acre-Foot
surf_area	Total Surface Area by Period	Land area covered by water in surface storage locations	Thousands of Acres
env_ben	Environmental Benefit from Flows	Economic benefits generated from natural flows for habitat maintenance and restoration	Thousands of US Dollars
tot_ben	Total Agricultural Benefits by Period	Cumulative yearly economic profits generated by the agricultural sector in the entire region	Thousands of US Dollars
dnpv_ben	Total Economic Benefits Over the Region	Sum of economic benefits generated by all sectors' water use in the region	Thousands of US Dollars
rec_ben	Recreation Benefit	Economic benefits generated from recreation activities such as fishing and boating on surface reservoirs per year	Thousands of US Dollars
tot_ag_pump	Total Agricultural Pumping	Volume of water pumped from the Mesilla and Hueco Bolson aquifers by each irrigation district	Thousands of Acre-Feet
gw_stocks	Groundwater Aquifer Stocks	Average estimated groundwater storage volume from the Mesilla and Hueco Bolson aquifers	Thousands of Acre-Feet
aquifer_depth	Aquifer Depth	Average Annual aquifer depth by period	Feet
a_return_o	Agricultural Return Flows from River to Aquifer	Residual irrigation water that was taken from the river and returned to underlying aquifer by year	Thousands of Acre-Feet
ag_pump_aq_rch	Agricultural Return from Pumping to Aquifer	Residual irrigation water that was pumped from underground aquifers and returned back to the underlying aquifer by year	Thousands of Acre-Feet
precip	Total Precipitation by Period	Estimated yearly volume of water derived from rainfall over surface reservoir areas	Thousands of Acre-Feet
tacres	Total Acreage by Crop	Total land area coverage used for the production of crops on a given year by each irrigation district	Thousands of Acres
tswacres	Total Surface Water Acreage	Reservoir surface area of water in acres	Thousands of Acres
tgwacres	Total Ground Water Acreage	Surface land area used for agricultural crop production that uses pumped groundwater	Thousands of Acres
ttacres	Total Acreage	Total land area coverage used for the production of crops on a given year by each irrigation district	Thousands of Acres
urb_back_use	Urban Substitute Technology Use	Effective volume of water consumed in the urban sector extracted from an alternative source with the use of technology such as blackish water desalination	Thousands of Acre-Feet
urb_back_aq_rch	Urban Return to Aquifer from Substitute Technology	Residual urban water extracted from an alternative source returned to an aquifer	Thousands of Acre-Feet
DNPV_ag_ben	Agricultural Benefits	Acumulated income generated by the agricultural sector over the projection period. The sum includes all irrigation districts	Thousands of US Dollars
ag_use	Agricultural Use	Effective volume of surface water and pumped water used for irrigation in each irrigation district per year	Thousands of Acre-Feet
tot_ag_bt_use	Agricultural Substitute Technology	Volume of water for agricultural use extracted from alternative sources from outside the local stream aquifer system	Thousands of Acre-Feet
shad_price_aqf	Cost of Aquifer Protection	Economic cost to protect aquifer storage to a user-specified level	US Dollars per Foot
DNPV_env_riv_ben	Environmental Benefits	Total amount of estimated benefits generated from habitat maintenance and restoration water flows over a set period of time	Thousands of US Dollars
DNPV_export_costs	Export Cost Benefits	Economic cost of exporting surface water due to excess supply not used	Thousands of US Dollars
Farm_income_gw	Farm Income from Aquifers	Total agriculture profits derived from the use of water from aquifer pumping by crop and district	Thousands of US Dollars
DNPV_import_costs	Import Cost Benefits	Regional profits generated from water importation due to local source scarcity	Thousands of US Dollars
net_recharge	Net Aquifer Recharge	Balance of yearly recharge or water depletion from the Mesilla and Hueco Bolson aquifers	Thousands of Acre-Feet
shad_price_ag_back_use	Price of Agricultural Substitute Technology	Unit cost of using alternative sources of water for the agriculture sector per year	Thousands of US Dollars
shad_price_urb_back_use	Price of Urban Substitute Technology	Unit cost of using alternative sources of water for the urban sector per year	Thousands of US Dollars
DNPV_rec_res_ben	Recreational Benefits	Total economic benefits generated in the projecton period from recreation activities such as fishing and boating on surface reservoirs	Thousands of US Dollars
shad_price_res	Reservoir Protection Cost	Approximate unit cost to maintain reservoirs at a user specified storage volume by a user specified time period	US Dollars per Foot
Farm_income_bt	Substitute Technology Farm Income	Farm income derived from water that was extracted from alternative sources with techonology use such as brackish water, desalination, or imports	Thousands of US Dollars
Farm_income_sw	Surface Water Farm Income	Economic profits generated in the agricultural sector derived from the use of surface reservoir water	Thousands of US Dollars
DNPV_urb_ben	Urban Benefits	Accumulated economic benefits generated by the urban water use over the projection time period with adjustment for inflation	Thousands of US Dollars

Contacts

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

Alex Mayer
Michigan Technical University
asmayer@mtu.edu

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