Susanna T.Y. Tong

The hydrologic effects of urban land use: A case study of the little Miami River Basin

Abstract This paper examines the impacts of urbanization on the Little Miami River Basin. Flood frequencies of an urbanizing town (Milford) and a rural area (Perintown) were analyzed based on the historical discharge data. Water samples were collected for chemical analyses and bioassays were conducted to determine the effects of runoff on seed germination and root development. The results of this study indicate that watershed urbanization has caused more frequent floods, poorer water quality and vegetation growth.

An integrated exploratory approach to examining the relationships of environmental stressors and fish responses

The Chesapeake Bay is one of the mostproductive systems in the world. It is theNations largest estuary (64,000 square miles)and is home to about 13 million people. Itsupports a variety of aquatic resources offlora and fauna. However, for the past 350years and especially in the last two to threedecades, there has been substantialdeterioration of the natural resources. Manyspecies of submerged aquatic vegetation andbenthic invertebrates have been diminished orbecome extinct. Commercial harvests of fish,crab and shell fish have also declined.In 1983, a Chesapeake Bay Agreement was signedby Pennsylvania, Maryland, the District ofColumbia, Virginia and the Bay Commission. Itwas subsequently amended in 1987 and 1992. TheAgreement identified the improvement andmaintenance of water quality as the mostcritical elements in the overall restorationand protection of the Chesapeake Bay. In orderto restore the Bay area and to conserve thefish resources, the causal relationshipsbetween the environmental stressors and thecomposition and health of the fish communitiesmust be understood.Multivariate ordination techniques are usefulexploratory tools to help elucidate latentenvironmental relationships, define specificbiocriteria and to generate hypotheses. Geographical information systems (GIS) is ananalytical technique for identifying spatialrelationships. In this project, an integratedmethodology involving the use of multivariateordination, statistical, and GIS techniques wasadopted. A non-metric multi-dimensionalscaling (NMDS) ordination technique wasemployed in conjunction with other statisticaltechniques (such as correlation analysis) andArcView GIS to analyze a huge data set from theMaryland Biological Stream Survey (MBSS). Theobjectives were to elucidate the intricaterelationships between a suite of environmentalfactors and fish conditions in the riverinesystem in the Chesapeake Bay and to evaluatethe effectiveness of this approach inexploratory analyses.The results showed that landuse issignificantly related to nutrient loading. Toa large extent, landuse and nitrates are alsoaffecting the composition and health of thefish communities in some subwatersheds in theChesapeake Bay. It was also found that theapproach adopted in this study is flexible,requiring few model assumptions. But it iscomprehensive and reliable, capable ofrevealing the impacts of environmentalstressors on the ecology, structure,composition and health of the fishcommunities.

Roadside dusts and soils contamination in Cincinnati, Ohio, USA.

Roadside dusts and soils were collected from various nonindustrial districts in Cincinnati, Ohio, USA, and analyzed for lead and copper contents. Results showed that the recent lead phase-down action has reduced the level of lead, but the concentrations of both metals are still higher than the background levels for normal soil. Elevated concentrations of copper in heavily traveled highways were noted, suggesting that much of the copper pollutants is probably of automotive origin. The concentration of lead was found to vary with housing age, and higher levels of contamination in the older neighborhoods were observed. This result is probably ascribable to the accumulation of residues from leaded gasoline and lead-based paint in the past and the use of coal fire for space heating in older houses.

Assessing the water quality impacts of future land-use changes in an urbanising watershed

An integrated watershed hydrologic model, the Soil and Water Assessment Tool (SWAT) was adopted in this study to simulate the water quality conditions under the current and the future land-use configurations. The findings were compared to determine the hydrologic consequences of future land-use changes. Results indicate that as the land use in the watershed shifts from predominantly agricultural to mixed rural and residential lands, a reduction in flow, sediments, and nutrients is detected. Although the projected average daily concentration of phosphorus is reduced by 47% under the future land-use scenario, it will still exceed the daily limit suggested by the US Environmental Protection Agency. From this study, it is evident that SWAT is a reliable water quality model, capable of producing accurate information for environmental decision-making. The model has a GIS interface and is coupled with the Better Assessment Science Integrating Point and Nonpoint Sources system. It is, therefore, a valuable tool for environmental informatics.

The retention of copper and lead particulate matter in plant foliage and forest soil

Abstract Soil and foliage samples were collected from 15 groves of American elders in the Mt. Airy Forest, Cincinnati, and tested for lead and copper concentrations. Analysis of variance revealed significant reduction of foliar copper and soil lead contents with distance into the forest; a result supporting the hypothesis suggested by Lederer (1982) and others that trees and shrubs not only beautify our cities, but are effective particulate interceptors. This ability of soil and vegetation acting as sinks for particulate matter contamination is especially beneficial in populated urban areas where ambient pollution levels tend to be high.

THE CONCENTRATION PROFILE OF HEAVY METALS IN AN URBAN FOREST

Abstract The concentration profile of copper and lead in the soil and foliage of an urban forest in Cincinnati, Ohio, was examined. The relationship of the profile to tree type, location, and vegetation, soil and site attributes was also studied. Results showed an elevated metal level near the forest edge and highway. Sites located in the forest interior had a much lower metal burden. Pine needles retained more metals, suggesting that they may be a good repository for airborne particles. Significant relationships between the foliar copper loadings with site aspect, elevation and slope angle were also identified.

Exploring the effects of population growth on future land use change in the Las Vegas Wash watershed: an integrated approach of geospatial modeling and analytics

The Las Vegas Valley metropolitan area is one of the fastest growing areas in the southwestern United States. The rapid urbanization has presented many environmental challenges. For instance, as population growth and urbanization continue, the supply of sufficient clean water will become a concern. In addition, the area is also experiencing the longest drought in history, and the volume of water storage in Lake Mead, the main fresh water supply for the entire region, has been reduced greatly. The water quality in the main stem of the Las Vegas Wash (LVW) and Lake Mead may also be significantly affected. In order to develop effective sustainable management plans, the very first step is to predict the plausible future urbanization and land use patterns. This paper presents an approach to predict the future land use pattern at the LVW watershed using a Markov cellular automata model. The multi-criteria evaluation was used to couple population density as a variable depicting the driving force of urbanization in the model. Moreover, landscape metrics were used to analyze land use changes in order to better understand the dynamics of urban development in the LVW watershed. The predicted future land use maps for the years 2030 and 2050 show substantial urban development in the area, much of which are located in areas sensitive to source water protections. The results of the analysis provide valuable information for local planners and policy makers, assisting their efforts in constructing alternative sustainable urban development schemes and environmental management strategies.

Modelling the hydrologic effects of land-use and climate changes

Climate and land use affect water quantity and quality; however, the complex relations of climate and land use regarding flow and instream nutrient levels have yet to be elucidated. This study aims to assess the hydrologic effects of different land-use and climatic regimes in the Lower Great Miami River Basin. The modelling results from BASINS showed that, as expected, agricultural lands and the wettest scenario yielded the highest amount of streamflow, fecal coliform, and nutrient loadings. But, it was the dry scenario (+2°C, -20% precipitation of the current average climatic conditions in SW Ohio), instead of the driest scenario (+4°C, -20% precipitation), that produced the highest daily nutrient concentrations. When the future land-use and climate scenarios were coupled, the worst situation was found under the current land use and the wettest condition. Hence, a change in land-use pattern may help to alleviate the adverse hydrologic impacts of climate change.

A total water management analysis of the Las Vegas Wash watershed, Nevada

Climate change, land-use change, and population growth are fundamental factors affecting future hydrologic conditions in streams, especially in arid regions with scarce water resources. Located in the arid southwest within the Las Vegas Wash watershed, Las Vegas is one of the fastest growing metropolitan areas of the country. In the past 30 years, because of climate and land-use changes, it has experienced a decrease in clean water supply but an increase in water demand. To alleviate some of these problems, large amounts of water have been pumped into the city from different sources, such as Lake Mead, and the urban wastewater is treated and returned back to the reservoir for water augmentation. However, in the face of continual global climate change and urbanization in the watershed, long-term planning for sustainable water management is critical. This research was designed to provide a comprehensive analysis incorporating hydrologic modeling, population projection, land-use change modeling, and water management policies to examine the total water balance and management options in this arid and rapidly urbanizing watershed under various scenarios of climate regime, population growth, land-use change, and total water management programs for the year 2050.

The use of non-metric multidimensional scaling as an ordination technique in resource survey and evaluation: a case study from southeast Spain

Abstract The potential contribution of non-metric multidimensional scaling (NMDS) ordination as a method of data reduction and hypothesis generation for resource survey was evaluated by using the amalgamated floristic and environmental data from three natural grazing areas in semi-arid lowland Murcia, southeast Spain. The results showed that the vegetation patterns were largely controlled by the effects of radiation receipt, rather than rainfall. This finding conflicts with results from a semi-arid environment in Australia (Noy-Meir 1974). Evidently, the technique is capable of revealing the latent environmental structure. As a rapid, flexible and effective tool, NMDS enhances straightforward, quantitative and objective interpretation, whereby inductive inferences on environmental structure can be readily formulated. The coordinate results also contain much important information of use in land use planning and resource management. NMDS therefore appears to be an invaluable tool in resource survey and evaluation and its use can complement other survey technologies, notably remote sensing and numeric classification.