GTA provides levee relief well observation, testing and rehabilitation services to our Clients, including municipalities, flood control district entities and system management consultants. We also work closely with Clients in the process of well replacement when necessary, providing drilling coordination and well construction observation services. GTA’s approach and methodologies are closely coordinated with reviewing agency requirements including the United States Army Corps of Engineers (USACE). The levee relief wells systems that GTA has evaluated were designed to relieve hydrostatic pressure at the base of the levee system. Water transmission efficacy of these wells is necessary for acceptable levee performance/stability. GTA’s observation and testing of the well systems provide a data stream used by the USACE and others for well performance evaluation and a determination as to the necessity of rehabilitation or replacement of underperforming wells. Our rehabilitation efforts have been successful in improving the transmission capacity of underperforming wells, under the auspices of USACE review. GTA’s levee relief well related services include the following:
- Well condition observation, photo-documentation
- Well sounding and groundwater level measurement
- Down-hole video services
- Sediment removal from inside of well casing/screen
- Hydraulic testing, including constant rate and step-drawdown testing
- Turbidity monitoring, Imhoff cone evaluation/sand content evaluation
- Water Quality sampling for laboratory analysis
- Down-hole geophysical services
- Downhole video and geophysics interpretation
- Hydraulic Test data analysis
- Well performance analysis and aquifer parameter estimation
- Rehabilitation via swabbing, surging and bailing/over-pumping
- Rehabilitation via alternative methods, e.g., has cooperated with and managed a crew using Hydropuls impulse generation technology for successful rehabilitation
- Act as liaison with well drillers for Client for design, scope of work for replacement wells
- Well drilling/construction observation
- Hydraulic testing of new wells for baseline performance data generation.
South Williamsport and Williamsport Levees, Lycoming County, PA
GTA performed levee relief well inspection, testing, and sediment removal services on 126 wells associated with the South Williamsport and Williamsport Levee systems, situated along the West Branch of the Susquehanna River. The wells are positioned at the toe of the levee and are designed to relieve hydrostatic pressure during flood conditions. GTA’s services consisted of the following:
- Removed sediment that had accumulated at the bottom of relief wells using an air-lift system designed by GTA.
- Performed step-drawdown pumping tests to estimate 24-hour specific capacity for each well.
- Down-hole video observation to evaluate the condition of well casing and screen.
The results of GTA’s testing and evaluation were submitted to the United States Army Corps of Engineers for their determination of additional rehabilitation measures, as may be applicable.
Wyoming Valley Relief Well Pump Testing, Luzerne County, PA
GTA performed inspection and testing of 128 relief wells located on the land side of the flood control levee system along the Susquehanna River. The relief wells are positioned at the toe of the levee and are designed to relieve hydrostatic pressure in the levees during flood conditions. The majority of the wells are located in open grass areas, with some located on gravel roads and parking areas near maintenance buildings and other facilities. GTA provided visual wellhead inspections and conducted hydraulic testing at 128 well locations across the project area. GTA compiled and analyzed all data, and reported wellhead condition observations, pump testing data, turbidity measurements, and estimated 24-hour specific capacity for each well meeting the criteria for specific capacity calculation.
Curwensville Dam Relief Wells, Curwensville, PA
Curwensville Dam is an earthen fill dam located on the West Branch of the Susquehanna River. GTA managed inspection, cleaning, and performance evaluation of 14 shallow overburden relief wells and 20 deep rock relief wells. These wells are located at the downstream toe of the Curwensville Dam and are designed to relieve hydrostatic pressure at the base of the dam. The following work was performed in the process of inspection, cleaning, and performance evaluation of the relief wells:
Performed wellhead visual inspection and wellhead photo documentation.
Performed pre-rehabilitation flushing and limited sediment removal in preparation for video inspection of the wells.
Managed pre-rehabilitation downhole video inspection of 24 relief wells.
Managed subconsultant utilizing Hydropuls® impulse generation technology in conjunction with GTA’s pumping and air lifting to rehabilitate the shallow and deep relief wells.
GTA and subconsultant conducted pre- and post-rehabilitation specific capacity testing of four shallow wells, and two deep wells.
Conducted post-rehabilitation recharge testing of the 34 relief wells.
Conducted post-rehabilitation 8-hour pump tests on 4 relief wells.
Compiled and managed all relative data, and submitted final report to USACE.