Lytle Water Solutions (LWS) has developed, and utilized in a variety of applications, numerical ground water models. Models have been developed to support litigation, optimize water supplies, evaluate ground water supply potential, and evaluate fate and transport of flow and water quality constituents. LWS has also peer-reviewed many existing numerical models to evaluate their applicability to their intended uses. Representative projects using numerical ground water models are described below.
Evaluation of Injury
Inflows to Lake McConaughy, in the panhandle of Nebraska, are being affected by the proliferation of ground water pumping upstream, along the North Platte River and along one of its major tributaries, Pumpkin Creek. Two separate MODFLOW numerical ground water models were developed, based on initial work conducted by the Cooperative Hydrology Study (COHYST) group, to assess and quantify the impacts of ground water pumping on Lake McConaughy inflows. The results of the models are being used to try to implement regulatory change to the management of ground water pumping. Ground water pumping depletions to surface flow are being quantified by individual users to assess potential damage.
A numerical ground water model of the Pumpkin Creek Basin is being used to support a civil suit by a surface water right holder to try and restore surface flows that have been depleted by upstream ground water pumping.
Water Supply Optimization
LWS personnel have developed, with input from a number of consultants, a MODFLOW surface water/ground water model of the Cherry Creek Basin (Colorado) to evaluate means to optimize the available resources, as well as maximize reuse opportunities. The basin-wide model was developed so that eight water supply entities could evaluate what options were viable to maximize available resources without being constrained by individual jurisdictional boundaries. The model accounts for both physical and legal availability of water.
Water Supply Potential
LWS personnel are peer-reviewing a USGS numerical MODFLOW model of the Lost Creek Designated Ground Water Basin (Colorado) to evaluate if it is representatively depicting the hydrology and hydraulics of the system. This review is particularly important because LWS will use this model, along with development of a water quality fate and transport component (MT3DMS), to evaluate water availability and water quality issues associated with potential municipal use of this water supply.
Fate and Transport
LWS is assisting the Cheyenne Board of Public Utilities (BOPU) with an assessment of the potential for aquifer storage and recovery (ASR) to be utilitzed at its well fields to increase productivity and sustainability. As part of this process, a MODFLOW numerical ground water model with particle tracking capability has been prepared to demonstrate the change in hydraulic gradients related to recharge, the downgradient movement of the recharged water while in underground storage, and the ability of BOPU to recapture this non-native water when needed (maintenance of dominion and control).
Water Rights / Permitting Issues
A MODFLOW numerical ground water model of the Lost Creek Designated Ground Water Basin (Colorado) will be used to support a Water Commission application for unappropriated water. The model is being evaluated to assure that it is representative of available water supplies so that it will be defensible in a Water Commission hearing setting.
The North Platte Natural Resources District (NPNRD) has imposed a ground water allocation for irrigation pumping in the North Platte River Basin above Lake McConaughy (Nebraska). The NPNRD is also preparing an Integrated Surface Water and Ground Water Management Plan (IMP) that is designed to sustain and balance uses within the basin. LWS has developed a numerical model to address issues with the allocation process and the proposed IMP and will use the results of the model to propose changes in allocations.