Bernard A. Engel

Web-Based Low Impact Development Decision Support Tool for Watershed Planning

Low Impact Development (LID) practices reduce pollution and hydrologic instability from stormwater arising from increases in impervious surfaces and land development practices. In response to increasing demands for information and tools to quickly and easily assess LID practices in comparison to conventional development practices, an easy to use web-based LID decision support and screening tool, L-THIA/LID, has been developed to evaluate the benefits of LID practices. The Long-Term Hydrologic Impact Assessment (L-THIA) web application is a decision support system based on the integration of web-based programs, geographic information system (GIS) capabilities, and databases. It provides information for decision makers on the impacts of water quantity and quality resulting from land use change. The web-based L-THIA/LID tool, which builds on L-THIA capabilities, will enable various stakeholders to quickly evaluate: (1) the impact of urban development on average annual runoff volume; and (2) the potential stormwater and pollutant reduction of proposed LID practices. Runoff quantity and water quality impacts of proposed land use change are displayed in tables, bar charts, and pie charts. The tools aim is to enable decision makers the ability to evaluate and understand the effects of LID practices and thus support effective watershed planning to achieve desired stormwater management goals.

Development of a SWAT ArcView GIS Patch for Accurate Analysis of Soil Erosion and Sediment Yield at Steep Sloping Watershed

Abstract: The watershed scale SWAT model divides the watershed into smaller subwatersheds for rainfall-runoff and pollutant generation at the field level and routing though stream networks. The SWAT model first needs to be calibrated and validated for accurate estimation through adjustment of various input parameters. However, in some instances the SWAT simulated results are greatly affected by the watershed delineation and DEM cell size. In this study, the SWAT ArcView GIS Patch II was developed for steep sloping watershed and its performance was evaluated for various threshold value and DEM cell size scenarios when delineating subwatersheds using SWAT. The SWAT ArcView GIS Patch II was developed using the ArcView GIS Avenue program and Spatial Analyst library. The SWAT ArcView GIS Patch II is better than the SWAT ArcView GIS Patch I by Lim et al. (2007) because it reflects the topographic factor in calculating the field slope length of the HRU in the SWAT model. The simulated sediment value for 321 watershed (threshold value of 200 ha) is greater than that for 43 subwatershed (threshold value of 25ha) by 201% without applying the SWAT ArcView GIS Patch II. However, when the SWAT ArcView GIS Patch II was applied, the difference decreases (12% difference) for the same scenario. The simulated sediment value for DEM cell size of 50m is greater than that for DEM cell size of 10m by 19.80% without the SWAT ArcView GIS Patch II. However, the difference becomes smaller (3.41% difference) between 50m and 10m DEM scenarios. As shown in this study, the SWAT ArcView GIS Patch II can reduce differences in simulated sediment values for various watershed delineation and DEM cell size scenarios. Without the SWAT ArcView GIS Patch II, variations in the SWAT simulated results using various watershed delineation and DEM cell size scenarios could be greater than those from input parameter calibration. The results obtained in this study show that the SWAT ArcView GIS Patch II needs to be used when simulating hydrology and water quality for steep sloping watersheds (especially if average slope of the subwatershed is greater than 25%) for accurate simulation of hydrology and water quality using the SWAT model. The SWAT ArcView GIS Patch II is available at http://www.EnvSys.co.kr/~swat for free download.

WEB-BASED DECISION SUPPORT SYSTEM FOR EVALUATION OF HYDROLOGICAL IMPACT OF URBAN SPRAWL

Decision support systems (DSS) that have been applied in the water engineering area were reviewed from na historical standpoint, and the DSS were described in terms of definition, structures and components. The nL-THIA web application that is a DSS based on an integration of WWW–based programs, GIS, and ndatabases is also introduced. The L-THIA web DSS was analyzed from the point of view of DSS structure nthat is comprised of a modeling system, database system and interface. As a DSS, L-THIA web has been nconstructed to support decision makers and to give them information about the hydrological impacts of nwater quantity and quality due to urban sprawl. To achieve these purposes, L-THIA web has a runoff and nNPS estimation model, internet-GIS and ORACLE based weather database. The L-THIA web has its own nspecial features that were prepared for novice users who are targeted as the potential users of the L-THIA nweb and would have limited knowledge about hydrology. Therefore, DSS enhancement features are nintroduced that provide useful functions like impact evaluation, treatment suggestions and urban best nmanagement practices (BMP) cost estimation. The enhancement features can help and guide users in ndecision making, and increase users’ comprehension about the effects of urban sprawl on water quantity nand quality.

Development of Web-based SWAT System

Non Point Source Pollution (NPSP) load had been arising as a significant environmental issue. Especially excessive NPS input to the water bodies is causing serious impacts on river or stream ecosystems worldwide. To develop efficient best management practices for water quality improvement, hot spot target areas first need to be identified and understood to develop proper action plans to restore river ecosystem. For simulation of NPSP influences on watershed, the Soil and Water Assessment Tool model (SWAT) has been widely used in many countries, by many researchers. But the SWAT model is a desktop-based system. Therefore there are many disadvantages over advantages of desktop-based system, especially when it is used for watershed management related decision making processes. In this study, the Web GIS-based SWAT system was developed, which provides Web GIS interface for the SWAT model installed on the server-side. The Web GIS-based SWAT provides simple-to-use interface to allow users to change the subbasin and HRU level input parameters, such as filter strip width, surface cover management, main channel slope, initial SCS CN II value, and so on. The Web-based SWAT system will provides valuable scientific information for watershed decision makers with ease-of-use Web GIS-based interface.

Development of Web GIS based VFSMOD System to Simulate Sediment Reduction Efficiency with Vegetative Filter Strip

In recent days, the Non Point Source Pollution has been arising as a big environmental issue. Especially muddy water problem is causing serious impacts on river ecosystem not only in Korea but also most of the countries. Accordingly many methods to manage and prevent this problem have been investigated such as greet chamber, reservoir or debris barrier. However, the VFS is thought to be the one of effective methods. However the effective width of the VFS first needs to be determined before VFS installation in the field. To provide ease-of-use interface with scientific VFS modeling engine, the Web GIS based VFSMOD system was developed in this study. The Web GIS based VFSMOD uses UH and VFSM as core engines to simulate rainfall-runoff and sediment trapping. The provide soil information of a point of interest, the Google Map interface to the Mapserver soil database system was developed using the Google Map API, Javascript, Perl/CGI, and Oracle DB programming. Two versions of the Web GIS based VFSMOD system were developed; one is Single Storm Event Analysis and the other is Multiple Storm Event Analysis options. With these two options in the Web GIS based VFSMOD system, the users can easily simulate the effects of filter strip under given rainfall event using the Single Storm Event Analysis mode and determine optimum filter strip width using the Multiple Storm Event Analysis mode. These two versions were applied to the study watershed located at Gangwon province in Korea to demonstrate how the Web GIS based VFSMOD system can be used in VFS analysis. It was found that the VFS efficiencies are dependant on storm amounts and filter strip width.

Internet Based SDSS for Watershed Management using Web-GIS Capability

Watershed management is a complicated process. A web-based spatial decision nsupport system (SDSS) was developed to assist with watershed hydrologic/water quality nassessment for present and future land uses. The SDSS was comprised of an integration of nweb–based programs, a hydrologic model, GIS and databases. The SDSS uses web-GIS ncapability for Internet map browsing, real time web-based watershed delineation and hydrologic nspatial data extraction to prepare input data for Long-Term Hydrologic Impact Assessment (LTHIA) nmodel operation. A watershed in suburban West Lafayette, IN undergoing urbanization nwas selected to illustrate the SDSS capability and to evaluate land use change impact on direct runoff and nonpoint source pollution. Although watershed management includes complicated nsteps and the online SDSS has restrictions due to the web environment, this web-based SDSS nhas potential applicability in assisting with watershed management decisions. The SDSS is noperational for supporting local communities, regional consulting companies and other nstakeholders at http://pasture.ecn.purdue.edu/~watergen.

EVALUATION OF LONG-TERM HYDROLOGICAL IMPACTS CAUSED BY URBANIZATION

A grid based hydrological model, CELTHYM, capable of estimating base flow and surface runoff with nreadily available data sets was applied to assess hydrological impacts caused by land use changes due to nurbanization. This study was conducted on a mid-west watershed, and the model was calibrated and nevaluated using observed stream flow data. Analysis of the ratio between direct runoff and total runoff and nthe change in rate of those ratios for increasing urban land use indicated that the increase of direct runoff nratio was proportional to the increase in the ratio of urban area. The results from the impact assessment of nland use change by the annual rainfall amount showed that the direct runoff ratio by land use changes were nnearly the same for the annual rainfall differences, but the dry year ratio of direct runoff to total runoff was nbigger than the ratio for the wet year. This result suggests that urbanization might be more harmful during ndry years than abundant rainfall years.

SATEEC GIS System for Spatiotemporal Analysis of Soil Erosion and Sediment Yield

Kyoung Jae Lim1, Youn Shik Park2, Bernard A. Engel2 and Nam Won Kim3 1Dept. of Regional Infrastructure Engineering, Kangwon National University, Kangwon, 2Dept. of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 2Dept. of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 3Korea Institute of Construction Technology, Goyang, Gyeonggi, 1,3Republic of Korea 2USA

Development of Web-based Load Duration Curve for Analysis of TMDL and Water Quality Characteristics

Abstract: The total maximum daily load (TMDL) program has been established for water quality restoration and management in watershed. The Load Duration Curve (LDC) has been used for appropriate TMDL targets determination. However, the related personals had to first learn to develop the LDC, and then collect flow and water quality data for a site of interest to generate LDC which is very much time-consuming. Thus, the web-based Load Duration Curve (LDC) System was developed using the Perl/CGI, GNUPLOT, JavaScript, and Google Map script for analysis of TMDL and water quality characteristics in watershed. This system provides users with various interfaces (flow and water quality input and uploading) for flow and water quality input to the system for generating LDC. Also, Google Map based interface is developed to retrieve daily stream flow data from remote USGS-server. Then the LDC is generated using these data automatically in 3-4 seconds. The Web-based LDC system (https://engineering.purdue.edu/~ldc; http://www.envsys.co.kr/~ldc), developed in this study, is an useful tool for characterizing the problem according to flow condition and proving a visual display to easily understand the problem and the TMDL targets. In addition, this system will be able to help decide appropriate BMPs with generated result for the watershed.

An Online Mapping Tool to Inform Pesticide Applicators of Sensitive Areas

Increases in application of some types of pesticides and registration of new products leads to an increasing concern held by producers of sensitive crops that pesticide drift and overspray problems may increase. This project seeks to allow producers of sensitive crops an avenue of communication to pesticide applicators. This tool was built on the familiar GoogleTM Maps interface. The online map was created where pesticide applicators would easily view the location of sensitive crops such as grapes, melons, and tomatoes and other vegetables, endangered species, and pesticide sensitive watersheds including those used for drinking water. The website has two components; one component will inform pesticide applicators and the other will allow growers of sensitive crops to register their locations. The location of sensitive areas is identified and registered by producers or producer organizations on high resolution aerial photos and then verified. The spatial database generated includes crop types and coordinates of the sensitive areas. Functionality includes the ability to pan and zoom in and out enabling on screen digitization or information retrieval at any scale. The tool also allows users to toggle through the satellite view, map view and hybrid view. When queried by the pesticide applicator, the site provides details of all potentially sensitive areas near the location of interest in Indiana.