2016 NGWA Groundwater Summit

Using a Hydraulic Profiling Tool in Site Characterization Activities

Monday, April 25, 2016: 3:00 p.m.
Confluence Ballroom C (The Westin Denver Downtown)
Todd K. Knause , Stanley Consultants Inc, Centennial, CO

Rapid, accurate subsurface characterization is critical to site investigations. The Hydraulic Profiling Tool (HPT) is a direct push logging tool that continuously measures the pressure required to inject a constant flow of water into the soil as the probe is advanced into the subsurface. The HPT allows for the creation of fast, continuous, real-time profiles of soil hydraulic properties in both fine- and coarse-grained material. The probe provides data about the formation lithology, permeability, and the piezometric profile, which allows for the development of detailed lithologic cross sections of the subsurface conditions and the detection of high electrical conductivity fluids (brines) in soil. 

The HPT was advanced down into a heterogenous alluvial deposit to a depth of 100 feet or refusal.  The hydrogeologic data collected was used to evaluate where to collect discrete soil and groundwater samples, and set monitoring well screens during the subsequent Sonic drilling activities. The pressure, flow, and electrical conductivity (EC) data is recorded on a series of logs providing real time high resolution site characterization data.  The injection pressure logs were used to infer hydrostratigraphy, including transmissive zones that may represent potential preferential migration pathways for groundwater contaminants and low permeable zones that may act as confining layers.  The EC measurements were used to evaluate lithology and potential Total Dissolved Solids (TDS) impacts to groundwater. Discrete groundwater samples were collected from highly transmissive zones, field tested for specific conductance, and submitted to a laboratory for TDS analysis to establish an appropriate ratio of conductivity to TDS.  Lithologic interpretations were confirmed by continuous soil cores collected with a Sonic drill rig during monitoring well installations.  Disturbed and undisturbed soil samples were collected and analyzed for chemical and physical properties.

Todd K. Knause, Stanley Consultants Inc, Centennial, CO
Todd Knause is a Professional Geologist and Senior Environmental Scientist with Stanley Consultants, Inc. He has over 30 years of experience assessing more than 1,500 properties in 34 states. These assessments include a wide variety of projects involving environmental site assessments, engineering geology, hydrogeology, and natural resources valuations. Todd has provided many types of services including EPA Brownfields redevelopment initiatives, CERCLA and RCRA audits, assessments, inspections and corrective actions; Phase I/II/III/IV ESAs, LUST investigations and cleanups, environmental liability evaluations, mineral and petroleum reserve estimates and economic analysis, mine planning and permit acquisition, subdivision design, and construction management.