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1.
The magnitude of the environmental and social consequences of soil erosion and land degradation in semiarid areas of the Mediterranean
region has long been recognized and studied. This paper investigates the interrelationship between land use/cover (LULC) changes
and land degradation using remotely sensed and ancillary data for southeastern Spain. The area of study, the Xaló River catchment
situated in the north of the Alicante Province, has been subjected to a number of LULC changes during the second half of the
20th century such as agricultural abandonment, forest fires, and tourist development. Aerial photographs dating back to 1956
were used for the delineation of historic LULC types; Landsat ETM+ data were used for the analysis and mapping of current
conditions. Two important indicators of land degradation, namely, susceptibility to surface runoff and soil erosion, were
estimated for the two dates using easily parametrizable models. The comparison of 1956 to 2000 conditions shows an overall
“recuperating” trend over the catchment and increased susceptibility to soil erosion only in 3% of the catchment area. The
results also identify potential degradation hot-spots where mitigation measures should be taken to prevent further degradation.
The readily implemented methodology, based on modest data requirements demonstrated by this study, is a useful tool for catchment
to regional scale land use change and land degradation studies and strategic planning for environmental management. 相似文献
2.
We analyzed the effects of changes in land cover on the water balance in Spain’s Marina Baixa County, on the Mediterranean
coast. To reveal how different land management strategies have affected the area’s environment, four municipalities within
the same catchment were studied: Benidorm, Callosa d’en Sarrià, Beniardà, and Guadalest. In the municipalities of Callosa
and Benidorm, the proportion of the area covered by woodland declined by 4.2% and 30.2%, respectively, and woodland was replaced
by agriculture and urban development. The abandonment of farmland produced a 17% increase in the proportion of the area covered
by vegetation in Guadalest and Beniardá, where frequent forest fires have exacerbated a decrease in the area of pine woodland.
Tourism development in Benidorm has been accompanied by an increase in the transportation infrastructure and by an expansion
of areas with an impermeable surface, with the lowest level of infiltration into the aquifer system. These changes have generated
a net water deficit in Callosa and Benidorm of more than 6 Mm3/year, creating a high demand for water imported from other municipalities (Guadalest and Beniardá) or from outside of the
county to maintain the sustainability of the current water management strategies. The Marina Baixa case study is representative
of many of the world’s coastal areas that are undergoing rapid urban development based on an inappropriate understanding of
human progress based mainly on economic development and thus provides insights into water management in other areas. 相似文献
3.
Data collected from 172 sites in 20 major river basins between 1993 and 1995 as part of the US Geological Survey's National
Water-Quality Assessment Program were analyzed to assess relations among basinwide land use (agriculture, forest, urban, range),
water physicochemistry, riparian condition, and fish community structure. A multimetric approach was used to develop regionally
referenced indices of fish community and riparian condition. Across large geographic areas, decreased riparian condition was
associated with water-quality constituents indicative of nonpoint source inputs—total nitrogen and suspended sediment and
basinwide urban land use. Decreased fish community condition was associated with increases in total dissolved solids and rangeland
use and decreases in riparian condition and agricultural land use. Fish community condition was relatively high even in areas
where agricultural land use was relatively high (>50% of the basin). Although agricultural land use can have deleterious effects
on fish communities, the results of this study suggest that other factors also may be important, including practices that
regulate the delivery of nutrients, suspended sediments, and total dissolved solids into streams. Across large geographic
scales, measures of water physicochemistry may be better indicators of fish community condition than basinwide land use. Whereas
numerous studies have indicated that riparian restorations are successful in specific cases, this analysis suggests the universal
importance of riparian zones to the maintenance and restoration of diverse fish communities in streams. 相似文献
4.
Land Use and Land Cover Change Analysis and Prediction in the Upper Reaches of the Minjiang River,China 总被引:1,自引:1,他引:1
Scientists have aimed at exploring land use and land cover change (LUCC) and modeling future landscape pattern in order to
improve our understanding of the causes and consequences of these phenomena. This study addresses LUCC in the upper reaches
of Minjiang River, China, from 1974 to 2000. Based on remotely sensed images, LUCC and landscape pattern change were assessed
using cross-tabulation and landscape metrics. Then, using the CLUE-S model, changes in area of four types of land cover were
predicted for two scenarios considering forest polices over the next 20 years. Results showed that forestland decreased from
1974 to 2000 due to continuous deforestation, while grassland and shrubland increased correspondingly. At the same time, the
farmland and settlement land increased dramatically. Landscape fragmentation in the study area accompanied these changes.
Forestland, grassland, and farmland take opposite trajectories in the two scenarios, as does landscape fragmentation. LUCC
has led to ecological consequences, such as biodiversity loss and lowering of ecological carrying capacity. 相似文献
5.
Providing clean water at relevant quality and quantity is a challenge that regulatory authorities have to face in metropolitan
cities that seem to develop at their limits of sustainability. Istanbul strives to face such a challenge for its population
of over 10 million, through six surface water resources. Two approaches of classification for the reservoirs are presented,
one based on current regulations and an alternative based on a more detailed classification. The results have shown that nutrient
control is the primary issue, and one of the reservoirs has already exceeded the limits of being eutrophic, one is at mesotrophic
conditions, and the remaining four are at the limit of being eutrophic, indicating the significance of making the correct
decision and taking pertinent measures for management and control. It has been observed that the only mesotrophic resource,
which also has the best general quality class, has no industry and a very low population density, whereas the one that is
already eutrophic is also the one with the lowest quality class, has the highest population density, and has the greatest
percentage of urban land use within its watershed. 相似文献
6.
Land use/cover in Northeast China went through extensive changes during the 1990s. This report explores the interaction between
these changes and the environment, and the implication of these changes for rational allocation of water resources. Two maps
of land use/cover produced from 1990 and 2000 Landsat TM satellite images were overlaid in ArcInfo to reveal changes in land
cover. Results indicate that farmland and grassland decreased by 386,195 and 140,075 ha, respectively, while water, built-up
areas, and woodland increased by 238,596, 194,231, and 192,682 ha, respectively. These changes bore a mutual relationship
with the environmental change. On the one hand, climate warming made some of these changes (e.g., conversion of woodland and
grassland to farmland) possible. On the other hand, the changed surface cover modified the local climate. These changes, in
turn, caused severe environmental degradation and increased flooding. The change between dry field and rice paddy, in particular,
raised severe implications for the proper allocation of limited water resources in the Northeast. Efforts are needed to coordinate
their rational allocation to reap maximum and sustainable return over the entire area, not just in some localities. Results
obtained in this study should be of interest to the international audience of Environmental Management in that they highlight the interactive nature of human activities and the environment and the off-site impact of these activities
on the environment. 相似文献
7.
Long-Term Effects of Changing Land Use Practices on Surface Water Quality in a Coastal River and Lagoonal Estuary 总被引:1,自引:0,他引:1
Meghan B. Rothenberger JoAnn M. Burkholder Cavell Brownie 《Environmental management》2009,44(3):505-523
The watershed of the Neuse River, a major tributary of the largest lagoonal estuary on the U.S. mainland, has sustained rapid
growth of human and swine populations. This study integrated a decade of available land cover and water quality data to examine
relationships between land use changes and surface water quality. Geographic Information Systems (GIS) analysis was used to
characterize 26 subbasins throughout the watershed for changes in land use during 1992–2001, considering urban, agricultural
(cropland, animal as pasture, and densities of confined animal feed operations [CAFOs]), forested, grassland, and wetland
categories and numbers of wastewater treatment plants (WWTPs). GIS was also used together with longitudinal regression analysis
to identify specific land use characteristics that influenced surface water quality. Total phosphorus concentrations were
significantly higher during summer in subbasins with high densities of WWTPs and CAFOs. Nitrate was significantly higher during
winter in subbasins with high numbers of WWTPs, and organic nitrogen was higher in subbasins with higher agricultural coverage,
especially with high coverage of pastures fertilized with animal manure. Ammonium concentrations were elevated after high
precipitation. Overall, wastewater discharges in the upper, increasingly urbanized Neuse basin and intensive swine agriculture
in the lower basin have been the highest contributors of nitrogen and phosphorus to receiving surface waters. Although nonpoint
sources have been emphasized in the eutrophication of rivers and estuaries such as the Neuse, point sources continue to be
major nutrient contributors in watersheds sustaining increasing human population growth. The described correlation and regression
analyses represent a rapid, reliable method to relate land use patterns to water quality, and they can be adapted to watersheds
in any region. 相似文献
8.
The importance of the surrounding landscape to aquatic ecosystems has been well established. Most research linking aquatic
ecosystems to landscapes has focused on the one-way effect of land on water. However, to understand fully the complex interactions
between aquatic and terrestrial ecosystems, aquatic ecosystems must be seen not only as receptors of human modification of
the landscape, but also as potential drivers of these modifications. We hypothesized that the presence of aquatic ecosystems
influences the spatial distribution of human land use/cover of the nearby landscape (≤1 km) and that this influence has changed
through time from the 1930s to the 1990s. To test this hypothesis, we compared the distribution of residential, agricultural,
and forested land use/cover around aquatic ecosystems (lakes, wetlands, and streams) to the overall regional land use/cover
proportion in an area in southeast Michigan, USA; we also compared the distribution of land use/cover around county roads/highway
and towns (known determinants of many land use/cover patterns) to the regional proportion. We found that lakes, wetlands,
and streams were strongly associated with the distribution of land use/cover, that each ecosystem type showed different patterns,
and that the magnitude of the association was at least as strong as the association with human features. We also found that
the area closest to aquatic ecosystems (<500 m) was more strongly associated with land use/cover distribution than areas further
away. Finally, we found that the strength of the association between aquatic ecosystems and land use/cover increased from
1938 to 1995, although the overall patterns were similar through time. Our results show that a more complete understanding
is needed of the role of aquatic ecosystems on the distribution of land use/cover. 相似文献
9.
Zambrano L Contreras V Mazari-Hiriart M Zarco-Arista AE 《Environmental management》2009,43(2):249-263
Awareness of environmental heterogeneity in ecosystems is critical for management and conservation. We used the Xochimilco
freshwater system to describe the relationship between heterogeneity and human activities. This tropical aquatic ecosystem
south of Mexico City is comprised of a network of interconnected canals and lakes that are influenced by agricultural and
urban activities. Environmental heterogeneity was characterized by spatially extensive surveys within four regions of Xochimilco
during rainy and dry seasons over 2 years. These surveys revealed a heterogeneous system that was shallow (1.1 m, SD = 0.4 ),
warm (17°C, SD = 2.9), well oxygenated (5.0 mg l−1, SD = 3), turbid (45.7 NTU SD = 26.96), and extremely nutrient-rich (NO3–N = 15.9 mg l−1, SD=13.7; NH4–N = 2.88 mg l−1, SD = 4.24; and PO4–P = 8.3 mg l−1, SD = 2.4). Most of the variables were not significantly different between years, but did differ between seasons, suggesting
a dynamic system within a span of a year but with a high resilience over longer periods of time. Maps were produced using
interpolations to describe distributions of all variables. There was no correlation between individual variables and land
use. Consequently, we searched for relationships using all variables together by generating a combined water quality index.
Significant differences in the index were apparent among the four regions. Index values also differed within individual region
and individual water bodies (e.g., within canals), indicating that Xochimilco has high local heterogeneity. Using this index
on a map helped to relate water quality to human activities and provides a simple and clear tool for managers and policymakers. 相似文献
10.
11.
基于梁子湖自然保护区1987年和2004年Landsat-TM影像遥感数据,在Erdas Imagine 8.5图像处理软件的支持下,结合野外实地考察,获得了土地利用现状图,通过对数据的统计分析,研究了保护区近20年来土地利用/土地覆盖的动态变化。研究表明:耕地和水域是保护区内的主要土地利用类型;近20年来,耕地、园地、林地、草地的面积都有减少,其中耕地面积减少了2320.816hm^2,减少比例达到11.78%,是面积减少最多的土地利用类型;居民点、交通、水域用地有所增加,其中池塘面积变化最大,增幅达到213.4%,是面积增加最多的土地利用类型,居民点用地增加了551.18hm^2,增幅达到59.07%,是增长幅度较大的土地利用类型。变化的原因主要是经济的发展、人口数量的增长和旅游业的发展。 相似文献
12.
Prakash Basnyat Lawrence Teeter B. Graeme Lockaby Kathryn M. Flynn 《Environmental management》2000,26(2):153-161
In this study, water quality and basin characteristics data from different basins of the Fish River basin, Baldwin County,
Alabama, were used to develop a valuation model. This valuation model is based on the effectiveness of “contributing zones”
identified and delineated using methods described by Basnyat and others (Environmental Management]1999] 23(4):539–549). The “contributing zone” delineation model suggests that depending on soil permeability, soil moisture,
depth to water table, slope, and vegetation, buffer widths varying from 16 m to 104 m must be maintained to assimilate or
detain more than 90% of the nitrate passing through the buffers. The economic model suggests the value of retiring lands (to
create the buffers) varies from $0 to $3067 per ha, depending on the types of crops currently grown. The total value of retiring
all areas identified by the contributing zone model is $1,125,639 for the study area. This land value will then form the basis
for estimates of the costs of land management options for improving (or maintaining) water quality throughout the study area. 相似文献
13.
Assessing Watershed-Scale, Long-Term Hydrologic Impacts of Land-Use Change Using a GIS-NPS Model 总被引:25,自引:0,他引:25
Land-use change, dominated by an increase in urban/impervious areas, has a significant impact on water resources. This includes
impacts on nonpoint source (NPS) pollution, which is the leading cause of degraded water quality in the United States. Traditional
hydrologic models focus on estimating peak discharges and NPS pollution from high-magnitude, episodic storms and successfully
address short-term, local-scale surface water management issues. However, runoff from small, low-frequency storms dominates
long-term hydrologic impacts, and existing hydrologic models are usually of limited use in assessing the long-term impacts
of land-use change. A long-term hydrologic impact assessment (L-THIA) model has been developed using the curve number (CN)
method. Long-term climatic records are used in combination with soils and land-use information to calculate average annual
runoff and NPS pollution at a watershed scale. The model is linked to a geographic information system (GIS) for convenient
generation and management of model input and output data, and advanced visualization of model results.
The L-THIA/NPS GIS model was applied to the Little Eagle Creek (LEC) watershed near Indianapolis, Indiana, USA. Historical
land-use scenarios for 1973, 1984, and 1991 were analyzed to track land-use change in the watershed and to assess impacts
on annual average runoff and NPS pollution from the watershed and its five subbasins. For the entire watershed between 1973
and 1991, an 18% increase in urban or impervious areas resulted in an estimated 80% increase in annual average runoff volume
and estimated increases of more than 50% in annual average loads for lead, copper, and zinc. Estimated nutrient (nitrogen
and phosphorus) loads decreased by 15% mainly because of loss of agricultural areas. The L-THIA/NPS GIS model is a powerful
tool for identifying environmentally sensitive areas in terms of NPS pollution potential and for evaluating alternative land
use scenarios for NPS pollution management. 相似文献
14.
Implications of Land Use/Land Cover Change in the Buffer Zone of a National Park in the Tropical Andes 总被引:2,自引:0,他引:2
The impacts of land use and land cover (LULC) change in buffer zones surrounding protected ecological reserves have important
implications for the management and conservation of these protected areas. This study examines the spatial and temporal patterns
of LULC change along the boundary of Rio Abiseo National Park in the Northern Peruvian Andes. Landscape change within four
ecological zones was evaluated based on trends expected to occur between 1987 and 2001. Landsat TM and ETM imagery were used
to produce LULC classification maps for both years using a hybrid supervised/unsupervised approach. LULC changes were measured
using landscape metrics and from-to change maps created by post-classification change detection. Contrary to expectations,
tropical upper wet montane forest increased despite being threatened by human-induced fires and cattle grazing of the highland
grasslands inside the park. Within the park’s buffer zone, tropical moist forest remnants were fragmented into more numerous
and smaller patches between 1987 and 2001; this was in part due to conversion into agricultural land. The methods used in
this study provide an effective way to monitor LULC change detection and support the management of protected areas and their
surrounding environments. 相似文献
15.
Mehmet B. Ercan Iman Maghami Benjamin D. Bowes Mohamed M. Morsy Jonathan L. Goodall 《Journal of the American Water Resources Association》2020,56(1):53-67
Climate change poses water resource challenges for many already water stressed watersheds throughout the world. One such watershed is the Upper Neuse Watershed in North Carolina, which serves as a water source for the large and growing Research Triangle Park region. The aim of this study was to quantify possible changes in the watershed’s water balance due to climate change. To do this, we used the Soil and Water Assessment Tool (SWAT) model forced with different climate scenarios for baseline, mid‐century, and end‐century time periods using five different downscaled General Circulation Models. Before running these scenarios, the SWAT model was calibrated and validated using daily streamflow records within the watershed. The study results suggest that, even under a mitigation scenario, precipitation will increase by 7.7% from the baseline to mid‐century time period and by 9.8% between the baseline and end‐century time period. Over the same periods, evapotranspiration (ET) would decrease by 5.5 and 7.6%, water yield would increase by 25.1% and 33.2%, and soil water would increase by 1.4% and 1.9%. Perhaps most importantly, the model results show, under a high emission scenario, large seasonal differences with ET estimated to decrease by up to 42% and water yield to increase by up to 157% in late summer and fall. Planning for the wetter predicted future and corresponding seasonal changes will be critical for mitigating the impacts of climate change on water resources. 相似文献
16.
Assessment of Future Climate Change Impact on Water Quality of Chungju Lake,South Korea,Using WASP Coupled with SWAT 总被引:1,自引:0,他引:1
Jong Y. Park Geun A. Park Seong J. Kim 《Journal of the American Water Resources Association》2013,49(6):1225-1238
This study is to evaluate the future potential impact of climate change on the water quality of Chungju Lake using the Water Quality Analysis Simulation Program (WASP). The lake has a storage capacity of 2.75 Gm3, maximum water surface of 65.7 km2, and forest‐dominant watershed of 6,642 km2. The impact on the lake from the watershed was evaluated by the Soil and Water Assessment Tool (SWAT). The WASP and SWAT were calibrated and validated using the monthly water temperatures from 1998 to 2003, lake water quality data (dissolved oxygen, total nitrogen [T‐N], total phosphorus [T‐P], and chlorophyll‐a [chl‐a]) and daily dam inflow, and monthly stream water quality (sediment, T‐N, and T‐P) data. For the future climate change scenario, the MIROC3.2 HiRes A1B was downscaled for 2020s, 2050s, and 2080s using the Change Factor statistical method. The 2080s temperature and precipitation showed an increase of +4.8°C and +34.4%, respectively, based on a 2000 baseline. For the 2080s watershed T‐N and T‐P loads of up to +87.3 and +19.6%, the 2080s lake T‐N and T‐P concentrations were projected to be 4.00 and 0.030 mg/l from 2.60 and 0.016 mg/l in 2000, respectively. The 2080s chl‐a concentration in the epilimnion and the maximum were 13.97 and 52.45 μg/l compared to 8.64 and 33.48 μg/l in 2000, respectively. The results show that the Chungju Lake will change from its mesotrophic state of 2000 to a eutrophic state by T‐P in the 2020s and by chl‐a in the 2080s. Editor's note: This paper is part of a featured series on Korean Hydrology. The series addresses the need for a new paradigm of river and watershed management for Korea due to climate and land use changes. 相似文献
17.
Yogesh P. Khare Christopher J. Martinez Gurpal S. Toor 《Journal of the American Water Resources Association》2012,48(6):1276-1293
Abstract: Spatial distribution of land use can have a substantial effect on surface and groundwater quality. Our objective was to test for trends in flow components and water quality related to changes in land use in the Alafia and Hillsborough River watersheds in Florida, USA, over the period 1974‐2007. In addition, water quality statistics were evaluated in the perspective of numeric water quality criteria and proposed reclassification of segments of the Alafia River. Trends in 10 water quality parameters and three discharge variables were evaluated using a nonparametric trend detection test. Results of land use analysis indicated substantial urbanization and loss of agricultural land in the study area. Discharge variables did not exhibit significant trends, whereas trends in the majority of water quality concentrations were negative or nonsignificant with total nitrogen and total Kjeldahl nitrogen as exceptions showing positive trends. Changes in nutrient pathways could not be clearly identified. Considering recently promulgated numeric nutrient criteria and standards for dissolved fluoride, much of the Alafia River was found to be out of compliance. While there were land use changes and changes in water quality over the study period, it was difficult to identify a direct cause‐effect relationship. Responses to regulatory efforts, such as the Clean Water Act and improvements in phosphate mining practices, may have had greater impacts on water quality than changes in land use. 相似文献
18.
Ge Sun Steven G. McNulty Jennifer A. Moore Myers Erika C. Cohen 《Journal of the American Water Resources Association》2008,44(6):1441-1457
Abstract: Assessment of long‐term impacts of projected changes in climate, population, and land use and land cover on regional water resource is critical to the sustainable development of the southeastern United States. The objective of this study was to fully budget annual water availability for water supply (precipitation ? evapotranspiration + groundwater supply + return flow) and demand from commercial, domestic, industrial, irrigation, livestock, mining, and thermoelectric uses. The Water Supply Stress Index and Water Supply Stress Index Ratio were developed to evaluate water stress conditions over time and across the 666 eight‐digit Hydrologic Unit Code basins in the 13 southeastern states. Predictions from two Global Circulation Models (CGC1 and HadCM2Sul), one land use change model, and one human population model, were integrated to project future water supply stress in 2020. We found that population increase greatly stressed water supply in metropolitan areas located in the Piedmont region and Florida. Predicted land use and land cover changes will have little effect on water quantity and water supply‐water demand relationship. In contrast, climate changes had the most pronounced effects on regional water supply and demand, especially in western Texas where water stress was historically highest in the study region. The simulation system developed by this study is useful for water resource planners to address water shortage problems such as those experienced during 2007 in the study region. Future studies should focus on refining the water supply term to include flow exchanges between watersheds and constraints of water quality and environmental flows to water availability for human use. 相似文献
19.
K.B. Khatri C. Strong N. von Stackelberg M. Buchert A.K. Kochanski 《Journal of the American Water Resources Association》2019,55(6):1540-1563
This study investigates the impact of climate and land use change on the magnitude and timing of streamflow and sediment yield in a snow‐dominated mountainous watershed in Salt Lake County, Utah using a scenario approach and the Hydrological Simulation Program — FORTRAN model for the 2040s (year 2035–2044) and 2090s (year 2085–2094). The climate scenarios were statistically and dynamically downscaled from global climate models. Land use and land cover (LULC) changes were estimated in two ways — from a regional planning scenario and from a deterministic model. Results indicate the mean daily streamflow in the Jordan River watershed will increase by an amount ranging from 11.2% to 14.5% in the 2040s and from 6.8% to 15.3% in the 2090s. The respective increases in sediment load in the 2040s and 2090s is projected to be 6.7% and 39.7% in the canyons and about 7.4% to 14.2% in the Jordan valley. The historical 50th percentile timing of streamflow and sediment load is projected to be shifted earlier by three to four weeks by mid‐century and four to eight weeks by late‐century. The projected streamflow and sediment load results establish a nonlinear relationship with each other and are highly sensitive to projected climate change. The predicted changes in streamflow and sediment yield will have implications for water supply, flood control and stormwater management. 相似文献