Project Overview
Introduction
Wetlands are known to accrete nutrients (N and P) and other contaminants. The Greater Everglades ecosystem has been impacted by agricultural and urban activities over several decades leading to phosphorus enrichment (DeBusk et al., 1994; DeBusk et al., 2001; Newman et al., 1997). The degree of nutrient enrichment depends both on nutrient loading and hydraulic retention time. This effect is distinct in many wetlands, and most notably in several hydrologic units of the Everglades, including water conservation areas, and the Everglades National Park.
Emerging geographic information technology enables us to integrate geospatial data of land and water resources derived from a variety of sources and to facilitate universal data sharing across the Internet. Sharing of information and spatial data with other users is outlined in the National Spatial Data Infrastructure (NSDI) (Clinton, 1994), a concept defined as the technologies, policies, and people necessary to promote sharing of geospatial data throughout all levels of government, the private and nonprofit sectors, and the academic community. Burrough (1986) defines a geographic information system (GIS) as a powerful set of tools for collecting, storing, retrieving, transforming, and displaying spatial data from the real world. WebGIS provides interactive GIS functionality delivered to end-users via the Internet and it has the potential to make distributed geographic information available to a worldwide audience (Cobb and Olivero, 1997; Green and Bossomaier, 2002). Users can access the geospatial information and data via web-browsers without purchasing expensive, proprietary GIS software. Data and map services can be implemented using WebGIS. Data services allows clients to retrieve spatial data and information from the Internet to local machines. In contrast, map services are constrained to online use and no data or information can be retrieved to local client machines.
Objectives Our objective was to develop an interactive web-based tool to integrate and visualize geospatial data and information for Florida’s wetlands providing map and data services to users.
Methodology We standardized and integrated 2130 geo-referenced point observations of 78 different soil physical, chemical, and biological attributes collected in Florida’s wetlands from 1987 to the present. These datasets were collected by scientists and staff of the Wetland Biogeochemistry Laboratory, Soil and Water Science Department, University of Florida and provide a valuable resource documenting historic and present environmental quality in Florida’s wetlands. The dataset is updated on a continuous basis to document current conditions in Florida's wetlands.
A WebGIS tool was created using ArcIMS software (ESRI Inc., Redlands, CA) to augment point observations with other GIS layers such as soils, geology, land use, and county boundaries providing query, selection, and navigation functions to users. Our server-side implementation allows clients to submit requests for data and map services to a Web server. The server processes the requests and returns data or a map to the remote clients’ web-browser.
A graphical interface was developed using VBScript to provide data services to users. They can run SQL-based queries and select specific data records using one or all of the following constraints: (i) geographic location, (ii) projection, (iii) time period, (iv) depth of sample, (v) vegetation type, and (vi) soil property. The selected data can be downloaded to local machines.
Results from a geostatistical analysis were made accessible using one of the provided datasets. The analysis was conducted using ArcGIS Geostatistical Analyst (ESRI Inc., Redlands, CA). The quantitative spatial analyses were used to describe the spatial patterns of total phosphorus. Different geostatistical techniques were employed to provide a better understanding of the spatial distribution and variability of soil quality parameters in the Everglades ecosystem.
Results and Discussion Users without GIS knowledge can intuitively explore the data. GIS maps can visually enhance the spatial and temporal understanding of phenomena and improve our interpretation of soil-landscapes and wetland ecosystems. Geo-data can be downloaded to client machines and augmented with other environmental datasets to document the ongoing restoration efforts in the Greater Everglades ecosystem.
References
Burrough P.A., 1986. Principles of Geographical Information Systems for Land Resources Assessment. Oxford University Press, Oxford.
Clinton W.J. 1994. Executive Order 12906 – edition of the Federal Register, 59(71): 17671-17674. Available at: http://www.fgdc.gov/nsdi/nsdi.html.
Cobb D.A. and A. Olivero. 1997. Online GIS services. J. of Academic Librarianship. 23(6): 484-507.
DeBusk, W.F., K.R. Reddy, M.S. Koch, and Y. Wang. 1994. Spatial distribution of soil nutrients in a northern Everglades marsh: Water Conservation Area 2A. Soil Sci. Soc. Am. J. 58:543-552.
DeBusk, W.F., S. Newman, and K.R. Reddy. 2001. Spatio-temporal patterns of soil phosphorus enrichment in Everglades WCA-2A. J. Environ. Qual. (30:1438).
Green D. and T. Bossomaier 2002. Online GIS and spatial metadata. New York, Taylor & Francis.
Newman S., K.R. Reddy, W.F. DeBusk, Y. Wang, G. Shih, and M.M. Fisher. 1997. Spatial distribution of soil nutrients in a Northern Everglades Marsh: Water Conservation Area 1. Soil Sci. Soc. Am. J. 61:1275-1283.