IMPACTS OF URBANIZATION ON SOIL QUALITY AND SUB-SURFACE ENVIRONMENT

The subsurface environment including soils have two basic functions: store and transmit water, and this means that it serves as a reservoir and a conduit system. The unsaturated zone of upper glacial aquifer with a thickness 50 feet in south east Queens was explored by auguring up to 120 cm depth with several 15 cm sections. The hydraulic conductivity is an important aquifer property that controls the groundwater flow and transport of contaminants dissolved in the water through soil. Hazen equation was used to determine the hydraulic conductivity. Cooper-Jacob straight line method will be eventually applied to understand the transmissivity and storativity of the aquifer. In this study, we investigated both unsaturated sediment zone in upper glacial aquifer (up to 120 cm) and top soil zone (up to 45 cm) of various parks in Queens County of New York City, NY, USA. For monitoring properties of the upper glacial aquifer, augur samples with multiple sections were collected from two spots next to two of the three monitoring wells completed by USGS (United States Geological Survey) at in the far corners of the York College parking lot and for soil characterization, at least one 45 cm core with multiple sections were collected from New York City Parks including Corona Meadow park, Bowne Pond park, Oakland lake Park, Baisley Pond park, Idlewild pak. The 15 cm sections were dried and sieved for the grain size distribution to obtain the hydraulic conductivity. A portable field tension infiltrometer was also used to understand the soil hydraulic conductivity and infiltration rate. The sections were categorized into bulk (<2 mm) and fine (<0.25 mm) from each core were analyzed for a suite of elements particularly focused on EPA RCRA elements by using handheld XRF (x-ray fluorescence spectrometry). NIST 2702 was run with each batch of 10 sections and was ± 3% within the reported value. The preliminary data showed wide distribution of chemical elements in the samples. These physical and chemical properties of soils and sub-surface materials are very critical to provide additional strength to existing environmental data and thus to help assessing and managing the current flooding problem and contaminant transport in south east Queens of New York City.