Hydrogeological / Geophysical Survey

A Hydrogeological and Geophysical Survey is the critical first step in any successful water well drilling project. At NASSA DRILLING & GENERAL SUPPLY LTD, we offer scientifically-driven subsurface investigations to identify optimal borehole locations, assess groundwater potential, and reduce the risk of dry or low-yield wells.

Our survey approach combines hydrogeological expertise with advanced geophysical techniques to provide a detailed understanding of underground water-bearing formations, soil and rock layers, and aquifer characteristics.

Objectives of the Survey

• Identify suitable locations for borehole drilling
• Determine the depth and thickness of aquifers
• Estimate potential yield and recharge rates
• Map subsurface geological structures (faults, fractures, dykes, etc.)
• Minimize the risk of dry or failed boreholes
• Support sustainable groundwater extraction planning

Survey Methods & Technology

Our team uses a combination of proven geophysical and hydrogeological techniques:

1. Vertical Electrical Sounding (VES)

• Measures resistivity of subsurface layers
• Determines depth and nature of water-bearing strata
• Effective for locating aquifers in sedimentary and basement terrains

2. Electromagnetic (EM) Profiling

• Detects lateral changes in subsurface conductivity
• Useful for identifying faults, fractures, and buried water channels

3. Ground Penetrating Radar (GPR) (optional, depending on site geology)

• High-resolution shallow subsurface imaging
• Ideal for identifying shallow aquifers or utilities

4. Hydrogeological Site Assessment

• Reviews rainfall data, topography, vegetation, and existing boreholes
• Assesses recharge potential and long-term sustainability
• Guides drilling depth and casing recommendations

Scope of Work

1. Pre-Survey Site Assessment
   • Review client needs and site history
   • Evaluate accessibility and suitability of proposed areas
2. Field Survey Execution
   • Use GPS and geophysical instruments to conduct surveys
   • Carry out multiple sounding points for accuracy
3. Data Analysis & Interpretation
   • Process data using modeling software (e.g., RES2DINV, IPI2Win)
   • Interpret geoelectric layers and aquifer potential
4. Reporting & Recommendations
   • Provide a full technical report with interpreted data
   • Suggest ideal drilling location(s), expected depth, and yield
   • Include borehole design recommendations (casing, screen depth, etc.)

Deliverables

• Detailed Hydrogeological & Geophysical Report
• Borehole Siting Map with GPS coordinates
• Vertical Sectional Diagrams of subsurface profiles
• Recommendations for drilling depth, casing, and pump capacity
• Consultation for any post-survey technical inquiries

Industries & Clients Served

• Government & NGO Water Projects
• Agricultural Irrigation Schemes
• Schools, Health Centers & Community Facilities
• Private Estates & Farms
• Industrial Plants & Mining Sites

Why Choose NASSA for Your Survey?

✅ Licensed Experts – Qualified hydrogeologists and geophysicists
✅ Modern Equipment – Reliable resistivity meters and EM tools
✅ Data-Driven Precision – Scientific decision-making for cost-effective drilling
✅ Local Terrain Expertise – Experience across various Tanzanian regions
✅ End-to-End Support – From site survey to drilling and pump installation