Water, Wastewater and Surface Water
dse provides technical services for a variety of water resources projects for water and wastewater utilities across the southwest and central United States. Services range from water resources planning, infrastructure needs analyses and system evaluation, alternative development, permitting, design and construction services. dse personnel are familiar with EPA and Texas Commission on Environmental Quality requirements for system design, capacity development, and system operation. In addition, dse personnel are familiar with federal and state infrastructure funding opportunities, including, but not limited to the USDA-Rural Development, and the TWDB State Revolving Fund Programs. Examples of dse experience include:
Former Carswell Air Force Base
Fort Worth, Texas
dse has performed quarterly monitoring of groundwater in more than twenty monitoring and recovery wells and surface waters at the former Carswell Air Force Base in Fort Worth, Texas for more than three years. All monitoring has been performed following AFCEE guidelines using low-flow techniques. All of the wells were gauged and tested for NAPLs before sampling. Both dedicated and portable bladder pumps have been used to purge and sample the monitoring and recovery wells in the AOC. All purged water was passed through a monitored flow-through cell and water levels were monitored to assure that the samples were representative of conditions in the impacted aquifer. In addition, surface water conditions have been monitored and water samples collected from several locations in the Trinity River.
dse prepared a general construction SWPPP to address requirements for conservation of soils and surface water during large scale construction. The site was approximately twenty acres of land being developed into residential property. Inspections of the control measures (silt fencing and drainage system) were conducted every two weeks and/or within forty-eight hours following a major rain event and at least once a quarter, during a rain event. These inspections were performed to see how the total drainage system, during construction, was functioning. Maintenance procedures were followed to keep the silt fencing in working order and also changed or augmented silt fencing, as needed, based off results of the inspections.
A spill of an unidentified substance occurred upstream to the Client’s property. The spill migrated onto the Client’s property and impacted a stocked lake located there. The spill impact possibly contributed to a fish kill in the lake. dse personnel visited the spill scene and documented the extent and impact of the spill. dse prepared a sampling plan and collected samples of impacted soils and water. The samples were analyzed for suspected chemicals of concern. dse reviewed the laboratory analyses results and prepared a report that documented our observations at the spill site and summarized our findings. dse personnel acted as an Expert Witnesses in the resulting litigation.
Watershed Planning and Rehabilitation
U.S. Department of Agriculture - Natural Resources Conservation Service (NRCS)
United States, Saipan, Guam, Caribbean
dse is managing the contract and providing environmental expertise including NEPA, EAs, EISs, and watershed management, from offices in Texas. dse is utilizing the extensive network of AMEC and other sub-consultant offices to provide local services to the NRCS state offices. The dse/AMEC Team are bringing the right resources and the best value to NRCS.
Groundwater and Contaminant Transport Modeling
Groundwater and contaminant flow are highly subjective and hard to predict in many instances. Regulatory agencies will often allow modeling to show, potentially, where and how the contaminants and groundwater are flowing. A recent project that illustrates dse capability to perform these services is:
Aberdeen Proving Grounds for Weston Solutions, Inc.
dse evaluated the remedial performance of a phytoremediation system to remediate an approximate 80 acre site that had been previously used for military munitions testing. The purpose of this evaluation was to:
- Estimate the degree of VOC plume capture (hydraulic containment) generated by the trees;
- Evaluate seasonal effects on tree’s capacity to contain the plume;
- Examine both the lateral and vertical extent of capture;
- Predict the remedial improvements gained by planting 600 additional trees.
dse reviewed the analyses of continuously collected groundwater level data from the previous 19 months. Data also included site-specific weather and tidal data. dse also periodically measured poplar tree transpiration rates, constructed seasonal water table maps, performed hydrograph analysis, developed a groundwater budget, and simulated the aquifer responses to phytoremediation using the MODFLOW computer groundwater model.