5 research outputs found
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Investigation of stream-aquifer interactions using a coupled surface water and groundwater flow model.
A finite element numerical model is developed for the modeling of coupled surface-water flow and ground-water flow. The mathematical treatment of subsurface flows follows the confined aquifer theory or the classical Dupuit approximation for unconfined aquifers whereas surface-water flows are treated with the kinematic wave approximation for open channel flow. A detailed discussion of the standard approaches to represent the coupling term is provided. In this work, a mathematical expression similar to Ohm's law is used to simulate the interacting term between the two major hydrological components. Contrary to the standard approach, the coupling term is incorporated through a boundary flux integral that arises naturally in the weak form of the governing equations rather than through a source term. It is found that in some cases, a branch cut needs to be introduced along the internal boundary representing the stream in order to define a simply connected domain, which is an essential requirement in the derivation of the weak form of the ground-water flow equation. The fast time scale characteristic of surface-water flows and the slow time scale characteristic of ground-water flows are clearly established, leading to the definition of three dimensionless parameters, namely, a Peclet number that inherits the disparity between both time scales, a flow number that relates the pumping rate and the streamflow, and a Biot number that relates the conductance at the river-aquifer interface to the aquifer conductance. The model, implemented in the Bill Williams River Basin, reproduces the observed streamflow patterns and the ground-water flow patterns. Fairly good results are obtained using multiple time steps in the simulation process
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Modeling of ground-water flow and surface water/ground-water interactions of the San Pedro River Basin, Cochise County, Arizona
Ground-water exploitation in the Upper San Pedro Basin has produced the formation of a cone of depression around the Sierra Vista-Fort Huachuca area. A portion of the mountain front recharge that otherwise would reach the San Pedro River is being intercepted by pumping, and portions of baseflow are being captured by pumping. The purpose of this study is to construct a simulation model capable of simulating the ground-water system as well as the ground-water-surface water interactions. The flow simulation was done by a three-dimensional, finite-difference ground-water flow model (MODFLOW) that incorporates a new stream-aquifer interaction package. Steady state simulations were performed to represent mean annual conditions. Transient simulations cover a 48 year period, starting in 1940 and ending in 1988. A sensitivity analysis of the steady state model was also performed
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Modeling of Ground-Water Flow and Surface/Ground-Water Interaction for the San Pedro River Basin Part I Mexican Border to Fairbank, Arizona
Many hydrologic basins in the southwest have seen their perennial streamflows turn to ephemeral, their riparian communities disappear or be jeopardized, and their aquifers suffer from severe overdrafts. Under -management of ground -water exploitation and of conjunctive use of surface and ground waters are the main reasons for these events.Research and development was supported in part by the Cochise County Flood
Control District, under grant provided by them. The views and conclusions contained
in this document are those of the authors and should not be interpreted as necessarily
representing the official policies, either expressed or implied, of the Cochise County
Flood Control District.
We would like to thank the members of the Upper San Pedro Water
Management Council (USPWMC) for there timely input and advice. This group
contributed a positive aspect to this endeavor. Special thanks to Eric Korsten and Ben
Lomeli whose sometime opposing views kept the authors on their tippy -tippy toes, to
Dennis Sundie whose love of cloud seeding is only surpassed by his patience in guiding
the USPWMC, to Bob McNish for acting as our guru and to Don Henderson for trying
to keep us technocrats focused on the real world.This title from the Hydrology & Water Resources Technical Reports collection is made available by the Department of Hydrology & Atmospheric Sciences and the University Libraries, University of Arizona. If you have questions about titles in this collection, please contact [email protected]
Recommended from our members
Investigations of stream-aquifer interactions using a coupled surface-water and ground-water flow model
A finite element numerical model is developed for the modeling of coupled surface-water flow and ground-water flow. The mathematical treatment of subsurface flows follows the confined aquifer theory or the classical Dupuit approximation for unconfined aquifers whereas surface-water flows are treated with the kinematic wave approximation for open channel flow. A detailed discussion of the standard approaches to represent the coupling term is provided. In this work, a mathematical expression similar to Ohm's law is used to simulate the interacting term between the two major hydrological components. Contrary to the standard approach, the coupling term is incorporated through a boundary flux integral that arises naturally in the weak form of the governing equations rather than through a source term. It is found that in some cases, a branch cut needs to be introduced along the internal boundary representing the stream in order to define a simply connected domain, which is an essential requirement in the derivation of the weak form of the ground-water flow equation. The fast time scale characteristic of surface-water flows and the slow time scale characteristic of ground-water flows are clearly established, leading to the definition of three dimensionless parameters, namely, a Peclet number that inherits the disparity between both time scales, a flow number that relates the pumping rate and the streamflow, and a Biot number that relates the conductance at the river-aquifer interface to the aquifer conductance. The model, implemented in the Bill Williams River Basin, reproduces the observed streamflow patterns and the ground-water flow patterns. Fairly good results are obtained using multiple time steps in the simulation process.This research was supported in part by the Fish and Wildlife Service. Its
sponsorship and in particular, the continuous support,we received from Steve Cullinan
and Les Cunningham is gratefully acknowledged. The research was also supported in part
by Microway Company with a gift of an I -860 board and software. Our thanks to Ann
and Steve Freid. The views and conclusions contained in this document are those of the
authors and should not be interrupted as necessarily representing the official policies,
either expressed or implied, of the Fish and Wildlife Service or of the Microway Company
Particular thanks go to Laurel Lacher and Shlomo P. Neuman for listening,
discussing ideas, and suggesting ideas.This title from the Hydrology & Water Resources Technical Reports collection is made available by the Department of Hydrology & Atmospheric Sciences and the University Libraries, University of Arizona. If you have questions about titles in this collection, please contact [email protected]
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Simulation of groundwater conditions in the Colorado River Delta, Mexico
The Colorado River Delta (CRD) is a large sedimentary complex within a tectonically active structurally controlled basin. The CRD lies across the U.S.-Mexico international boundary and is traversed by the Colorado River on is way to the Gulf of California. Multidisciplinary research addressing the impact of the hydrologic change in the CRD has been increasing since the 1980's. To help expand the base of this knowledge, a groundwater model for the CRD within Mexico was developed. A conceptual model was constructed and transformed within the Department of Defense Groundwater Modeling Software (GMS) into a numerical model using the MODFLOW 2005 code made available by the U.S. Geological Survey. Model results indicates that large scale flood events on the Colorado River act as a recharge to the aquifer and show that the relationship between groundwater withdrawals and capture are evident on an seasonal scale. The model will form the parent basis for further Delta studies using the Local Grid Refinement (LRG), a methodology inherent to MODFLOW 2005.Support for this work was provided by the David and Lucile Packard Foundation and the
Thinker Foundation. We are also grateful to the National Water Commission office in
Mexicali Baja California, in particular Ing. Francisco Tellez and Ing. Julio Navarro, for
data provided for this work. Dr. Jorge Ramirez and Ing. Jose Trejo from Autonomous
University of Baja California also provided insights and recommendations to build this
model.
This work was also supported by the United States Agency for International
Development (USAID) funded Training, Exchanges, Internships, and Scholarships
(TIES) partnership program "Partnership for Improved Management of Watershed
Resources in the Lower Colorado River." Research and development for this model was
also supported in part by the National Science Foundation Science and Technology
Center for Sustainability of Semi-Arid Hydrology and Riparian Areas (SAHRA).
We are grateful to the National Water Commission (CONAGUA) in Mexico - office in
Mexicali Baja California, in particular Ing. Francisco Tellez and Ing. Julio Navarro, for
data and input provided for this work. Dr. Jorge RamÃrez- Hernandez and Ing. José Trejo
Alvarado from Autonomous University of Baja California also provided insights and
recommendations to build this model.This title from the Hydrology & Water Resources Technical Reports collection is made available by the Department of Hydrology & Atmospheric Sciences and the University Libraries, University of Arizona. If you have questions about titles in this collection, please contact [email protected]