The availability of reliable, safe water supplies is crucial to the health and livelihood of communities throughout the world, particularly in semi-arid environments.

GLA’s experts in hydrology, hydrogeology, and related disciplines provides technical guidance that can be relied upon to ensure optimal development, use, and management of groundwater, surface water, and recycled water resources.

Our professionals conduct specialized technical analyses to support water resources management decisions such as evaluation of stream-aquifer interactions, quantification of recharge rates, aquifer characterization, and computer modeling. Additionally, our broad environmental expertise allows us to draw on other specialties, such as cleanup of groundwater contamination, that are relevant to impacted or threatened public supplies.

Our graphic design, geographic information systems, and database capabilities allow us to efficiently and effectively store, retrieve, analyze, and present water resources data to technical audiences and the public.

GLA’s scope of water resources services includes:

  • Data management
  • Environmental litigation/expert services
  • Groundwater modeling
  • Groundwater recharge/reuse
  • Stormwater management
  • Water resources planning
  • Water storage distribution systems
  • Watershed management
  • Water/wastewater engineering
  • Wells/wellfields


GLA-Data is a user-friendly, web-accessible, geographic information system (GIS)-based database management system (DBMS or DMS) that has been developed to manage, store, map, visualize, and report water resources and environmental data. Clients have the option to provide broad public access or various permission-based levels of accessibility that facilitate stakeholder engagement and informational transparency as needed.

GLA-Data has been customized for a range of water well management priorities, such as California Groundwater Sustainability Management Act (SGMA) reporting and compliance for Groundwater Sustainability Plans (GSPs) for California Groundwater Sustainability Agencies (GSAs); well registration, permitting, and reporting for Texas groundwater conservation districts (GCDs) and large landholders; for a range of entities to manage well data and analyze water quality information, such as managing groundwater monitoring well-related and water supply processes.

The following active sites are accessible to the public, for example:

Fillmore and Piru Groundwater Basins GLA-Data site

Owens Valley Groundwater Basin GLA-Data site

Sierra Valley Groundwater Basin GLA-Data site

Big Valley (Lake County) Groundwater Basin GLA-Data site

Learn More

Environmental Litigation/Expert Services

In support of environmental, water resource, and water rights legal disputes, the GLA companies provide technical expertise to attorneys and mediators. Areas of expertise include:

  • Confidential consulting during all phases of dispute resolution
  • Technical assistance during alternative dispute resolution (ADR), litigation, mediation, settlement negotiations
  • Expert opinion reports and declarations
  • Expert testimony and depositions
  • Environmental database development and management
  • Visual aids for courtroom exhibits and conceptual renderings

Our reputation for technical integrity is based on sound science. Our experts include specialists in contaminant fate and transport, hydrogeology, hydrology, and geochemistry.


Disputes over water rights can be highly contentious and the process of applying for or transferring water rights can be technically and legally complex. Our professionals provide expert testimony when necessary, and lend technical expertise and experience with legal and regulatory programs to clients through the process of negotiating for the purchase, lease, or transfer of water rights.

GLA staff members perform technical analyses related to the evaluation or identification of the potential water rights or water resources available to support new or existing needs; development of groundwater models; negotiation for purchase, lease, or transfer of water rights; and hydrogeologic analyses to establish well yields, water quality, and safe yield of groundwater basins.

Our staff have legal expertise in working within the frameworks of interstate water compacts, pueblo and tribal water rights, state adjudication and administrative processes, and other agreements and operational protocols under which water rights are administered.

Groundwater Modeling

Understanding the past, present, and future movement of water and contaminants in the hydrologic cycle is essential to making wise environmental decisions. One of the most advanced methods available to gain this understanding is computer modeling, and its applications are highly diverse. Computer modeling is a vital component of our suite of professional services. GLA’s computer modeling capabilities cover a full spectrum, ranging from the application of simple analytical solutions to state-of-the-art, highly complex numerical computer codes. Our projects range from detailed simulation of the subsurface flow and transport within a small area, to simulation of groundwater recharge and flow through geologically complex aquifer systems over an area of hundreds of square miles.

In support of our simulation efforts, GLA offers advanced database services and geographic information system (GIS) technology for analysis of site data. The strength of our modeling group lies in the combination of extensive practical experience and strong academic backgrounds. Our modeling professionals have published their findings in peer-reviewed journals and have been selected by the EPA to develop computer codes and guidance for national dissemination. We consistently meet the challenge to develop new and innovative simulation approaches to address the needs of our clients.

Our modeling services include:

  • Groundwater flow and groundwater-surface water interaction (e.g., all USGS MODFLOW versions including NWT and USG, MODFLOW-SURFACT, FEFLOW)
  • Contaminant fate and transport modeling (e.g., MT3DMS , MT3D-USGS, MODFLOW-SURFACT, FEFLOW)
  • Density-dependent groundwater flow and solute transport (e.g., SEAWAT, MOCDENS, SUTRA)
  • Watershed recharge modeling (e.g., INFIL and DPWM)
  • Vadose zone modeling (e.g., HYDRUS, MODFLOW-SURFACT, UNSAT-H)
  • Geochemical modeling (e.g., PHREEQC and Geochemist Workbench)
  • Fully coupled groundwater flow and geochemical modeling (e.g., PHT3D)
  • Non-aqueous phase liquid and vapor transport modeling (e.g., T2VOC)
  • Landfill performance modeling (e.g., HELP and UNSAT-H)
  • Geologic modeling and 3D visualization (e.g., Leapfrog Geo and Leapfrog Hydro)
  • Parameter estimation/nonlinear optimization (e.g., PEST, UCODE)
  • Hydraulic modeling
  • Site visualization and analysis
  • Water balance modeling
  • Groundwater basin numerical modeling
  • Recharge and infiltration studies
  • Seepage studies
  • Statistical analyses

Groundwater Recharge/Reuse

GLA is familiar with various state recycled water policies and offers proven strategies and the resources necessary to successfully overcome regulatory obstacles. We work with our clients, regulators, potential water users, and other stakeholders to ensure maximum reuse of the water.

Managed aquifer recharge (MAR), also known as aquifer storage and recovery (ASR), allows water managers to store excess supplies available only seasonally for use during peak periods of demand. Water is recharged to the aquifer system and recovered at a later date. Because MAR relies on water storage in the subsurface, communities save water that would be lost to evaporation if stored in a reservoir. Based on our expertise in vadose zone processes, the GLA team has become a national leader in design and implementation of MAR systems using surface infiltration and direct injection recharge methods.

Stormwater Management

GLA’s hydrologists assist clients in navigating regulations regarding stormwater runoff, including flood control hydraulic analysis and point source discharge compliance with the Environmental Protection Agency (EPA) National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) requirements. Our expertise includes addressing permitting challenges cost-effectively and ensuring regulatory compliance, developing stormwater pollution prevention plans (SWPPPs), and preparing stormwater quality sampling plans and programs. We review and analyze sampling data to establish the significance of illicit and stormwater discharge constituents.

Stormwater quality best management practices (BMPs) are not one-size-fits-all. We help our clients to evaluate and pinpoint those BMPs that work best with each client’s unique stormwater incidence and conveyance system. Our services include water sampling, infrastructure monitoring, and preparation and implementation of SWPPPs. Where appropriate, we can assist clients in meeting stormwater discharge requirements by performing low-impact development (LID) studies and designs to infiltrate, evapotranspire, and reuse runoff on site.

Our engineers assess the hydrologic and subsurface conditions and the capacity, functionality, and quality of the stormwater systems to develop creative solutions that solve nuisance water problems caused by flooding and/or improper and/or insufficient infrastructure.

Water Resources Planning

Sound scientific data are only one component of water resources planning. Many other sociological, ecological, and environmental factors influence the decision-making process, which often results in a complex planning environment.

GLA works with state and local governments, water districts, and private water companies to assist with making the best use of limited water resources. Our planners augment or support state, regional, and local water plans and programs to enhance water supply, quality, and sustainability. We regularly participate in the Environmental Impact Report (EIR) process for complex development and water use projects, including water supply assessments. Our professionals also perform water rights analyses and acquisition when needed to secure a sustainable water supply.

Since public and stakeholder involvement is critical to an effective and implementable plan, we regularly conduct public involvement and stakeholder participation processes.

Key planning services include:

  • Groundwater sustainability plans
  • Groundwater management plans
  • Regional water plans
  • Drought management
  • Aquifer safe yield studies
  • Water master plans
  • Urban water management plans
  • Demand forecasting
  • Public involvement
  • Water resource management plans
  • Water quality protection plans
  • Salt and nutrient management planning
  • Water rights
  • Decision support
  • Environmental permitting
  • Conservation planning

Water Storage and Distribution Systems

Water managers require that a consistent supply of water flows to all parts of the community, in real time, on-demand and in perpetuity. Effective water storage and distribution systems are based on properly designed and constructed infrastructure. GLA has helped clients to evaluate water transmission and distribution systems, water storage, and pumping. Our professionals combine practical scientific knowledge with standard engineering principles to provide conceptual planning to full-scale design and construction services. The storage and distribution system must be designed to accommodate growth and environmental changes as well as ever-advancing technology.

Pairing water system modeling software with our broad understanding of EPA and state regulations, GLA provides efficient, economical solutions to water system challenges for communities small and large.

Watershed Management

GLA works with land and resource managers to keep forests healthy and protect water quality. We have worked extensively on forest and range land in the central and western U.S., where fire danger and wildfire impacts have been a major concern in recent years.

Key services include:

  • Storm runoff water quality sampling and data analysis
  • Watershed recharge modeling
  • Nonpoint source pollution management
  • Erosion control
  • Watershed restoration
  • Low-impact development (LID) studies
  • Mudflow/debris-flow hazard analysis and mitigation
  • Forest thinning
  • Archaeological and biological survey coordination
  • Catastrophic fire response

Water/Wastewater Engineering

Municipal water distribution and wastewater collection and treatment are the cornerstone components of any community’s infrastructure. GLA’s professionals optimize the efficiency of these systems through a comprehensive approach to planning, design and construction of needed facilities. GLA also assists communities and local governments in ensuring that their systems meet the rigorous regulatory compliance requirements of both state and federal regulatory agencies. In addition, the GLA team works to assist communities in procuring funds through grant and loan programs in order to subsidize the cost of their water and wastewater projects.

Key water and wastewater services include:

  • Water towers, wells & distribution systems
  • Treatment plants
  • Regulatory agency compliance
  • Facilities planning
  • Discharge permit renewal
  • Collection system maintenance & rehabilitation
  • Pumping/booster stations
  • Funding procurement
  • Master plan development
  • Computer modeling


GLA has considerable experience with permitting, design, construction, development, testing, and maintenance of water supply wells. Well analysis typically includes evaluating existing hydrogeologic data to determine the depth to water, underlying lithology, anticipated discharge rate, and groundwater quality. Our experience ranges from shallow, small-capacity wells to deep, high-capacity well fields serving entire cities with growing populations. Our design activities incorporate state-of-the-art modeling and hydrogeologic analysis. Once the design is complete, we develop specifications, provide bidding assistance, and perform well construction oversight on water supply projects.

Key services in water supply development include:

  • Geophysical logging oversight and analysis
  • Exploratory drilling and hydrogeologic characterization
  • Aquifer testing
  • Identification of production zones
  • Municipal well and well field design and development
  • Permitting
  • Water rights analysis and acquisition
  • Conjunctive use studies
  • Brackish water development
  • Construction oversight
  • Water quality assessments
  • Brine and residual disposal
  • Regional water plans
  • State water plans
  • 40-year water development plans

GLA has experience evaluating salinity in both groundwater supplies. To evaluate deep groundwater quality, we perform packer testing and incremental plugging of geologic strata in wells to isolate potential brackish aquifer zones and optimize groundwater quality and production. GLA employs a full suite of geophysical logging capabilities along with detailed lithologic descriptions of representative geologic formation samples and innovative downhole camera techniques. GLA also characterizes the geochemical and isotopic composition of river water in order to identify sources of salinity.

The quantity of reject water concentrate created from the desalination process is one of the most demanding problems to be resolved for successful implementation of a desalination project. Depending on the concentration of the feed water, recovery efficiencies range broadly, requiring reject water to be disposed of or put to other beneficial reuse. Methods of disposal include sewer discharge, land application, and deep well injection. Evaporation ponds require large areas of land, liner construction, and permitting challenges. GLA has the resources and expertise to investigate formations for concentrated brine injection, install the required monitoring wells, and assist in acquiring the necessary permits for the deep injection wells.