Adam Weinberg UEP 232 9/13/2012 Assignment 1: Project Topic Residents of Sharon, Massachusetts, have documented habitat distress in the lower reaches of Beaver Brook, a tributary of the Neponset River, approximately 18 miles south-southwest of Boston. It has been proposed by a local watershed advocacy group that groundwater pumping by a municipal supply well is withdrawing water from Beaver Brook, located approximately 250 ft. from the well. This withdrawal may be responsible for degradation of the health of the Beaver Brook ecosystem to detrimental effect upon a variety of aquatic species, including a population of brook trout. To study the flow impacts on Beaver Brook stream flow, stream-gauges were installed upstream and downstream of the municipal well and volunteers have collected streamflow data since 2007. A typical watershed exhibits increased stream-flow further downstream, as the contributing source area for the stream increases. Data collected from the stream-gauges indicates that, during the summer months, Beaver Brook exhibits the opposite behavior. Activists suggest this is evidence that municipal groundwater pumping is depleting stream-flow from Beaver Brook. The questions I hope to address in this project are: 1) Are there any points between the two stream-gauges where surface-water is being naturally diverted and unaccounted for? Local knowledge suggests that there are no diversions between the gauges that would impact the stream, but I have no current method to confirm this. 2) Does the spatial data provide any explanations for why Beaver Brook is losing water besides groundwater pumping? It may be possible that the surficial geology is such that the stream will naturally infiltrate into the aquifer in the lower reaches of the stream when groundwater levels are lowered by increased evaporation and plant transpiration during the summer. Base maps that will be necessary or otherwise informative include topography, geology, and land-use maps. Geology and topography are public domain data available through the United States Geological Survey (USGS). Land-use maps are available through the MA Department of Fish and Game (MA FWE). Other data required for this project is also publically available information. Stream-gauge and rain-gauge data were obtained from the MA FWE River Instream Flow Stewards (RIFLS) website. Groundwater pumping data was obtained from the Town of Sharon Department of Public Works (DPW). The location of stream-gauges is noted on maps and GPS coordinates also provided by municipal features including pumping and monitoring wells were obtained from the DPW. Sources 1. Garbrecht, J., Ogden, F., DeBarry, P., and Maidment, D. (2001). GIS and Distributed Watershed Models. I: Data Coverages and Sources. Journal of Hydrological Engineering, 6(6), 506–514. The first of a two paper series about GIS and Distributed Watershed Models identifies “types and sources of spatial data … illustrates GIS capabilities, and addresses GIS-model integration and implementation issues” related to hydrological applications of GIS. There is a great introduction to raster and vector data, map projections, and how this can be applied to stream and drainage data. Much of the digitized stream data and other hydrographic data is available through USGS or USEPA. Local scale soils data is available through the Soil Survey Geographic (SSURGO) database. 2. Gerstner, C., Vogel, R. (2008). Paving Paradise: Watershed Imperviousness and Peak Streamflow. [PowerPoint slides]. Tufts University Dissertation, retrieved from scholarworks.umass.edu via Google Scholar. This Tufts thesis combined GIS with hydro-statistical analysis. One of the aspects of greatest interest to me is that Gerstner used several methods to infer permeability of land surface. There were direct methods using MassGIS Imperviousness and National Land Cover Datasets. However, she also inferred permeability using other datasets such as land cover and population density, and by applying equations or coefficients to these datasets. Therefore, even if a particular dataset of interest does not exist, it may be possible to infer data from other sources by applying scientifically rigorous methods to evaluate the data. 3. Jones, K.L., Poole, G.C., O’Daniel, S.J., Mertes, L.A.K., Sanford, J.A. (2008). Surface Hydrology of Low-Relief Landscapes: Assessing Surface Water Flow Impedance Using LIDAR-derived Digital Elevation Models. Remote Sensing of Environment 112(11): 4148-4158. This article warns that typical Digital Elevation Models (DEMs) may not be adequate for determining hydrological flow characteristics of low topography environments with GIS. DEMs are useful for high-relief environments, but in basins where subtle topographic divides can have significant impacts on local hydrology, alternative data sources may be necessary. This study found that using light detection and ranging (LiDAR) methods, 1-meter resolution maps of flow impendences/ topographic divides were possible. These types of maps require a different type of flow analysis- link and node network routing. Since my proposed study area is a fairly small subbasin in south-eastern Massachusetts, it is likely that this watershed could be considered lowrelief. While I am unsure whether such LiDAR data is available for this site, this paper is a great reminder that the resolution of the data sources I utilize will be critical. 4. Ogden, F., Garbrecht, J., DeBarry, P., and Johnson, L. (2001). GIS and Distributed Watershed Models. II: Modules, Interfaces, and Models. Journal of Hydrological Engineering 6(6), 515–523. The second paper is the GIS and Distributed Watershed Models series discusses applications that are available to model hydrological characteristics of a watershed basin using GIS. Many of these applications seem to be designed as modules to be used with GIS programs such as ArcGIS. GRID, a component of ArcGIS, is potentially the most applicable module discussed in the paper. GRID allows flow direction to be determined from a raster-based elevation dataset. Flow accumulation can calculate the upstream drainage area at any particular point, and a watershed function delineates that upstream area. I will attempt to access and use the GRID module or some equivalent in my project as the flow direction, flow accumulation, and watershed functions would all be very helpful. 5. Pickering, N., Rowe, G., Clarkeson, J., Jacqz, C. (2008). Using Water Budgets to Assess Impacts on Streamflow. [PowerPoint slides]. Retrieved from scholarworks.umass.edu via Google Scholar. This source is a power-point presentation jointly prepared by the Charles River Watershed Association, the MA Executive Office of Energy and Environment, MassGIS, and the environmental consulting firm ESS Group. The presentation proposes that water budgets allow assessment of human impacts on streamflow. The water budgets are evaluated to the sub-basin scale on monthly time-steps. The hydrology is evaluated for stream base-flow, urban impacts to streamflow, and impacts of utilities according to absolute impact (gallons, cfs) and relative impact (% of natural flow). The calculations were performed using the ArcGIS Visual Basic Tool. Water budget inputs and outputs are summarized and methodologies for data inputs explained. Well withdrawals were converted to stream depletion using a USGS tool called StrmDepl, which I also will be using for my thesis. This presentation confirms that my plan to evaluate the Beaver Brook water budget using GIS is possible, and potentially is a powerful tool. 6. Rosenthal, W.D., Rrinivasan, R., Arnold, J.G. (1995). Alternative River Management Using a Linked GIS-Hydrology Model. Trans. ASAE 47(4): 1039-1049. This paper utilizes a GIS-hydrological model link to predict streamflow. This highly complex hydrological simulation uses daily time-step data within a GIS framework. The layers utilized include a digital elevation model (DEM) topographic map, soils data from STATSGO, and land use and land cover data from USGS. Daily precipitation and temperature data from the National Weather Service were utilized. While the model developed in this paper is far more complex than I can hope to use, the fact that GIS and daily time-step data was integrated has a great deal of applicability for my project.