Estimating Local Ground-Water Flow Conditions in a Granitoid: Preliminary Assessments in the Waldoboro Pluton Complex, Maine

Periodic dry wells are reported by some homeowners in Knox and Lincoln Counties, Maine. These wells pump from the migmatitic Bucksport Fm. which is intermixed with the granitoids of the Waldoboro Pluton Complex. Previous remote sensing and geologic mapping delineated marked northeast-trending structures in the WPC which were initially suspected as influencing ground-water flow for sustainable well yields. A sample area, Pemaquid Pond, in the WPC was studied in more detail including preliminary hydraulic testing of homeowner wells and ground-waiter flow modeling. Wells with sustainable and greater yields appear to be associated instead with zones of northwest-trending structures in granitoids not intermixed with the Bucksport Fm. Dry wells appear to be more prevalent amongst northeast-trending structures in areas where the migmatitic metamorphic rocks outcrop. Hydraulic studies, including pumping, slug, pressure, and borehole dilution testing, resulted in a wide range of calculated hydraulic conductivities. Dual-porosity flow modeling and geostatistical parameterization of the flow conditions suggest that the anisotropic hydraulic conductivity is near E-9 m/d.     

Influence of Elevation Data Source on 2D Hydraulic Modelling

The aim of this paper is to analyse the influence of the source of various elevation data on hydraulic modelling in open channels. In the research, digital terrain models from different datasets were evaluated and used in two-dimensional hydraulic models. The following aerial and satellite elevation data were used to create the representation of terrain–digital terrain model: airborne laser scanning, image matching, elevation data collected in the LPIS, EuroDEM, and ASTER GDEM. From the results of five 2D hydrodynamic models with different input elevation data, the maximum depth and flow velocity of water were derived and compared with the results of the most accurate ALS data. For such an analysis a statistical evaluation and differences between hydraulic modelling results were prepared. The presented research proved the importance of the quality of elevation data in hydraulic modelling and showed that only ALS and photogrammetric data can be the most reliable elevation data source in accurate 2D hydraulic modelling.