Digital map of hydraulic conductivity for the High Plains Aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

Groundwater is the world's most important freshwater resource. Despite this importance, groundwater flow and interactions between groundwater and other parts of the hydrological cycle are often neglected or simplified in large-scale hydrological models. One of the challenges in simulating groundwater flow and continental to global scales is the lack of consistent globally available hydrogeological data. These input data are needed for a more realistic physical representation of the groundwater system, enabling the simulation of groundwater head dynamics and lateral flows. A realistic representation of the subsurface is especially important as large-scale hydrological models move to finer resolutions and aim to provide accurate and locally relevant hydrologic information everywhere. In this study, we aim at improving and extending on current available large-scale data sets providing information of the subsurface. We present a detailed aquifer representation for the continental United States and Canada at hyper resolution (250 × 250 m). We integrate local hydrogeological information, including observations of aquifer layer thickness, conductivity, and vertical structure, to obtain representative aquifer parameter values applicable to the continental scale. The methods used are simple and can be expanded to other parts of the world. Hydrological simulations were performed using the integrated hydrological model ParFlow and demonstrated improved model performance when using the new aquifer parameterization. Our results support that more detailed and accurate aquifer parameterization will advance our understanding of the groundwater system at larger scales. Plain Language SummaryGroundwater is the largest available freshwater resource humans can use for drinking and growing food. It is stored beneath our feet in thick layers of sand or rock; we call these layers aquifers. For a realistic estimation of how much groundwater is stored and flows through these aquifers, detailed information on the properties of these layers is essential. However, this information is often missing, or not detailed enough, at the larger scales. In this study, we introduce a new method to obtain this detailed data by including information from observations and local-scale studies what we upscaled to the continent of North America. We estimate aquifer parameters at very high spatial resolution over a large domain. These data were not available previously. We evaluate our newly obtained aquifer parameterization against other existing data sets and tested model sensitivity to different horizontal and vertical resolutions and conductivity values. We used the integrated hydrological model ParFlow.Our results show that estimates of water table depth improved using our new parameterization. The methods we introduce here can be used by other modelers looking to improve their aquifer parameterization. We hope that our study can be used as a road map towards improved and more detailed aquifer parameterization used in current large-scale hydrological mo...

Section: Test Case Region and Model Runsmentioning

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Section: Test Case Region and Model Runsmentioning

confidence: 99%

See 1 more Smart Citation

Hyper‐Resolution Continental‐Scale 3‐D Aquifer Parameterization for Groundwater Modeling

Graaf

Condon

Maxwell

2020

“…

ϕ_{i}

is the soil type of well i and

γ_{r}

is a fixed effect for the local groundwater management district (GWMD)

r .

We include GWMD fixed effects to control for unobserved heterogeneity that potentially exists between GWMDs. Hydraulic conductivity (HC) describes the ease with which water moves through a porous medium and HC measures for the study area were obtained from a US Geologic Survey data source (Cederstrand & Becker, ). Specifically, HC is a dummy variable for hydraulic conductivity greater than 20 ft/d.…”

Section: Resultsmentioning

confidence: 99%

The Heterogeneous Impacts of Groundwater Management Policies in the Republican River Basin of Colorado

Hrozencik

Manning

Suter

et al. 2017

Groundwater is a critical input to agricultural production across the globe. Current groundwater pumping rates frequently exceed recharge, often by a substantial amount, leading to groundwater depletion and potential declines in agricultural profits over time. As a result, many regions reliant on irrigated agriculture have proposed policies to manage groundwater use. Even when gains from aquifer management exist, there is little information about how policies affect individual producers sharing the resource. In this paper, we investigate the variability of groundwater management policy impacts across heterogeneous agricultural producers. To measure these impacts, we develop a hydroeconomic model that captures the important role of well capacity, productivity of water, and weather uncertainty. We use the model to simulate the impacts of groundwater management policies on producers in the High Plains aquifer of eastern Colorado and compare outcomes to a no‐policy baseline. The management policies considered include a pumping fee, a quantity restriction, and an irrigated acreage fee. We find that well capacity and soil type affect policy impacts but in ways that can qualitatively differ across policy type. Model results have important implications for the distributional impacts and political acceptability of groundwater management policies.

“…This groundwater elevation is subtracted from the bedrock elevation [ Macfarlane and Wilson , 2006] to obtain the predevelopment saturated thickness presented in the inset maps using contour intervals of 30 m. This elevation was subtracted from a kriged surface of groundwater elevation in 2005 between observation wells [ Hausberger et al , 1998] to obtain the observed changes in saturated thickness presented using contour intervals of 5 m. The Universal Kriging algorithm in ArcGIS was used to spatially average the saturated thickness over the study region, and the values used for H 0 and the slope of the aquifer base are delineated in Table 1. Other important hydrogeologic variables in this table include hydraulic conductivity, k , and specific yield, S y , from Cederstrand and Becker [1998c, 1998b], and α is computed using = H 0 .…”

Section: Application and Discussionmentioning

confidence: 99%

Groundwater response to changing water‐use practices in sloping aquifers using convolution of transient response functions

Steward

Yang

Chacon

2009

[1] This study examines the impact of a sloping base on the movement of transients through groundwater systems. Dimensionless variables and regression of model results are employed to develop functions relating the transient change in saturated thickness to the distance upgradient and downgradient from recharge or withdrawal. Convolution of these transient response functions (made possible due to linearity of partial differential equations in the model) enables computation of changes in saturated thickness over recharge/withdrawal that varies over space and time. Establishing the criteria and form of these functions led to the discovery of fundamental underlying properties: upgradient and downgradient responses may be scaled to achieve a symmetrical relationship, expressions are developed to compute change in saturated thickness at the location of water use, and downgradient response at large times form a S-shaped curve that effectively adds a diffusive component to the average velocity of the kinematic wave approximation, where the hydraulic gradient is equal to the bed slope. Hydrogeologic data for three study regions in the High Plains Aquifer are summarized, and model results are presented for changes in saturated thickness. The transient response functions are used to reconstruct and interpret groundwater response to historical water-use practices and to predict future changes in saturated thickness for a series of hypothetical alternative water-use scenarios. Depressions in groundwater elevation are observed both upgradient and downgradient from areas of high water use; however, these depressions preferentially move downgradient over time and may continue to spread downgradient far into the future. This approach quantifies and provides understanding of the impacts of changes in natural and anthropogenic hydrologic forcings on aquifer systems.