The effect of climate and land use change on flow duration in the Maryland Piedmont region

This paper describes the use of a continuous streamflow model to examine the effects of climate and land use change on flow duration in six urbanizing watersheds in the Maryland Piedmont region. The hydrologic model is coupled with an optimization routine to achieve an agreement between observed and simulated streamflow. Future predictions are made for three scenarios: future climate change, land use change, and jointly varying climate and land use. Future climate is modelled using precipitation and temperature predictions for the Canadian Climate Centre (CCC) and Hadley climate models. Results show that a significant increase in temperature under the CCC climate predictions produces a decreasing trend in low flows. A significant increasing trend in precipitation under the Hadley climate predictions produces an increasing trend in peak flows. Land use change by itself, as simulated by an additional 10% increase in imperviousness (from 20·5 to 30·5%), produces no significant changes in the simulated flow durations. However, coupling the effects of land use change with climate change leads to more significant decreasing trends in low flows under the CCC climate predictions and more significant increasing trends in peak flows under Hadley climate predictions than when climate change alone is employed. These findings indicate that combined land use and climate change can result in more significant hydrologic change than either driver acting alone. Copyright © 2008 John Wiley & Sons, Ltd.     

Individual and combined effects of land use/cover and climate change on Wolf Bay watershed streamflow in southern Alabama

Land use/cover (LULC) and climate change are two main factors affecting watershed hydrology. In this paper, individual and combined impacts of LULC and climate change on hydrologic processes were analysed applying the model Soil and Water Assessment Tool in a coastal Alabama watershed in USA. Temporally and spatially downscaled Global Circulation Model outputs predict a slight increase in precipitation in the study area, which is also projected to experience substantial urban growth in the future. Changes in flow frequency and volume in the 2030s (2016–2040) compared to a baseline period (1984–2008) at daily, monthly and annual time scales were explored. A redistribution of daily streamflow is projected when either climate or LULC change was considered. High flows are predicted to increase, while low flows are expected to decrease. Combined change effect results in a more noticeable and uneven distribution of daily streamflow. Monthly average streamflow and surface runoff are projected to increase in spring and winter, but especially in fall. LULC change does not have a significant effect on monthly average streamflow, but the change affects partitioning of streamflow, causing higher surface runoff and lower baseflow. The combined effect leads to a dramatic increase in monthly average streamflow with a stronger increasing trend in surface runoff and decreasing trend in baseflow. Copyright © 2013 John Wiley & Sons, Ltd.     

Regression‐based approach to low flow prediction in the Maryland Piedmont region under joint climate and land use change

We examine the low flow records for six urbanized watersheds in the Maryland Piedmont region and develop regression equations to predict annual minimum low flow events. The effects of both future climate (based on precipitation and temperature projections from two climate models: Hadley and the Canadian Climate Centre (CCC)) and land use change are incorporated to illustrate possible future trends in low flows. A regression modelling approach is pursued to predict the minimum annual 7‐day low flow estimates for the proposed future scenarios. A regional regression model was calibrated with between 10 and 50 years of daily precipitation, daily average temperature, annual imperviousness, and the daily observed flow time‐series across six watersheds. Future simulations based on a 55 km² urbanizing watershed just north of Washington, DC, were performed. When land use and climate change were employed singly, the former predicted no trends in low flows and the latter predicted significant increasing trends under Hadley and no trends under CCC. When employed jointly, however, low flows were predicted to decrease significantly under CCC, whereas Hadley predicted no significant trends in low flows. Antecedent precipitation was the most influential predictor on low flows, followed by urbanization. Copyright © 2006 John Wiley & Sons, Ltd.     

Modelling the effects of land use and climate changes on hydrology in the Ursern Valley,Switzerland

While many studies have been conducted in mountainous catchments to examine the impact of climate change on hydrology, the interactions between climate changes and land use components have largely unknown impacts on hydrology in alpine regions. They need to be given special attention in order to devise possible strategies concerning general development in these regions. Thus, the main aim was to examine the impact of land use (i.e. bushland expansion) and climate changes (i.e. increase of temperature) on hydrology by model simulations. For this purpose, the physically based WaSiM‐ETH model was applied to the catchment of Ursern Valley in the central Alps (191 km²) over the period of 1983?2005. Modelling results showed that the reduction of the mean monthly discharge during the summer period is due primarily to the retreat of snow discharge in time and secondarily to the reduction in the glacier surface area together with its retreat in time, rather than the increase in the evapotranspiration due to the expansion of the “green alder” on the expense of grassland. The significant decrease in summer discharge during July, August and September shows a change in the regime from b‐glacio‐nival to nivo‐glacial. These changes are confirmed by the modeling results that attest to a temporal shift in snowmelt and glacier discharge towards earlier in the year: March, April and May for snowmelt and May and June for glacier discharge. It is expected that the yearly total discharge due to the land use changes will be reduced by 0.6% in the near future, whereas, it will be reduced by about 5% if climate change is also taken into account. Copyright © 2013 John Wiley & Sons, Ltd.     

Balancing trade‐off issues in land use change and the impact on streamflow and salinity management

The south‐west region of the Goulburn–Broken catchment in the south‐eastern Murray–Darling Basin in Australia faces a range of natural resource challenges. A balanced strategy is required to achieve the contrasting objectives of remediation of land salinization and reducing salt export, while maintaining water supply security to satisfy human consumption and support ecosystems. This study linked the Catchment Analysis Tool (CAT), comprising a suite of farming system models, to the catchment‐scale CATNode hydrological model to investigate the effects of land use change and climate variation on catchment streamflow and salt export. The modelling explored and contrasted the impacts of a series of different revegetation and climate scenarios. The results indicated that targeted revegetation to only satisfy biodiversity outcomes within a catchment is unlikely to have much greater impact on streamflow and salt load in comparison with simple random plantings. Additionally, the results also indicated that revegetation to achieve salt export reduction can effectively reduce salt export while having a disproportionately smaller affect on streamflows. Furthermore, streamflow declines can be minimized by targeting revegetation activities without significantly altering salt export. The study also found that climate change scenarios will have an equal if not more significant impact on these issues over the next 70 years. Uncertainty in CATNode streamflow predictions was investigated because of the effect of parameter uncertainty. Copyright © 2012 John Wiley & Sons, Ltd.     

Assessing the impact of climate variability and human activities on streamflow from the Wuding River basin in China

Located in the Loess Plateau of China, the Wuding River basin (30 261 km²) contributes significantly to the total sediment yield in the Yellow River. To reduce sediment yield from the catchment, large-scale soil conservation measures have been implemented in the last four decades. These included building terraces and sediment-trapping dams and changing land cover by planting trees and improving pastures. It is important to assess the impact of these measures on the hydrology of the catchment and to provide a scientific basis for future soil conservation planning. The non-parametric Mann–Kendall–Sneyers rank test was employed to detect trends and changes in annual streamflow for the period of 1961 to 1997. Two methods were used to assess the impact of climate variability on mean annual streamflow. The first is based on a framework describing the sensitivity of annual streamflow to precipitation and potential evaporation, and the second relies on relationships between annual streamflow and precipitation. The two methods produced consistent results. A significant downward trend was found for annual streamflow, and an abrupt change occurred in 1972. The reduction in annual streamflow between 1972 and 1997 was 42% compared with the baseline period (1961–1971). Flood-season streamflow showed an even greater reduction of 49%. The streamflow regime of the catchment showed a relative reduction of 31% for most percentile flows, except for low flows, which showed a 57% reduction. The soil conservation measures reduced streamflow variability, leading to more uniform streamflow. It was estimated that the soil conservation measures account for 87% of the total reduction in mean annual streamflow in the period of 1972 to 1997, and the reduction due to changes in precipitation and potential evaporation was 13%. Copyright © 2007 John Wiley & Sons, Ltd.     

Modeling the climatic effects of the land use/cover change in eastern China

This study aims to quantify the contribution of land use/cover change (LUCC) during the last three decades to climate change conditions in eastern China. The effects of farmland expansion in Northeast China, grassland degradation in Northwest China, and deforestation in South China were simulated using the Weather Research and Forecasting (WRF) model in addition to the latest actual land cover datasets. The simulated results show that when forestland is converted to farmland, the air temperature decreased owing to an increase in surface albedo in Northeast China. The climatic effect of grassland degradation on the Loess Plateau was insignificant because of the negligible difference in albedo between grassland and cropland. In South China, deforestation generally led to a decrease in temperature. Furthermore, the temperature decrease caused by the increase in albedo counteracted the warming effects of the evapotranspiration decrease, so the summer temperature change was not significant in South China. Excluding the effects of urbanization in the North China Plain, the LUCC effects across the entire region of East China presented an overall cooling trend. However, the variation in temperature scale and magnitude was less in summer than that in winter. This result is due mainly to the cooling caused by the increase in albedo offset partly by the increase in temperature caused by the decrease in evaporation in summer. Summer precipitation showed a trend of increasing–decreasing–increasing from southeast to northwest after LUCC, which was induced mainly by the decrease in surface roughness and cyclone circulations appearing northwest of Northeast China, in the middle of the Loess Plateau, and in Yunnan province at 700 hPa after forests were converted into farmland. All results will be instructive for understanding the influence of LUCC on regional climate and future land planning in practice.     

River discharge,land use change,and surface water quality in the Xiangjiang River,China

To compare the impacts of river discharge on the surface water quality of the Xiangjiang River in China, 12 surface water quality parameters recorded at 31 sampling sites from January 1998 to December 2008 along the river and its main tributaries were analyzed. Significantly higher concentrations of total nitrogen, ammoniacal nitrogen, and total phosphorus, and biochemical oxygen demand were observed during low‐flow periods than during high‐flow periods, implying a higher risk to local residents drinking untreated water during low‐flow periods. Pollution indexes, including the inorganic pollution index and integrated pollution index (IPI), were negatively related to impervious surface area (ISA) and cropland area (CLA) when ISA (CLA) was less than 160 (3000) km². However, the relationship was positive when ISA (CLA) was larger than 160 (3000) km², which provided a reasonable explanation for the observed spatial patterns of water quality. Distinct increasing temporal trends for two kinds of pollution indexes were also found. The annual ISA was significantly related to the rapid degradation of water quality from 1998 to 2008, with correlation coefficient (r) values of 0.816 (p = 0.002) and 0.711 (p = 0.014) for the organic pollution index (OPI) and IPI, respectively. However, annual rainfall was negatively correlated with the two indexes with r values of 0.785 (p = 0.002) and 0.448 (p = 0.093) for OPI and IPI, respectively. Our study highlights that decision makers should be more aware of recent increases in the pollution of the Xiangjiang River, especially at downriver sites and during low‐flow periods. Copyright © 2013 John Wiley & Sons, Ltd.     

Simulated runoff responses to land use in the middle and upstream reaches of Taoerhe River basin,Northeast China,in wet,average and dry years

Study on runoff variations and responses can lay a foundation for flood control, water allocation and integrated river basin management. This study applied the Soil and Water Assessment Tool model to simulate the effects of land use on annual and monthly runoff in the Middle and Upstream Reaches of Taoerhe River basin, Northeast China, under the wet, average and dry climate conditions through scenario analysis. The results showed that from the early 1970s to 2000, land use change with an increase in farmland (17.0%) and decreases in forest (10.6%), grassland (4.6%) and water body (3.1%) caused increases in annual and monthly runoff. This effect was more distinct in the wet season or in the wet year, suggesting that land use change from the early 1970s to 2000 may increase the flood potential in the wet season. Increases in precipitation and air temperature from the average to wet year led to annual and monthly (March and from June to December) runoff increases, while a decrease in precipitation and an increase in air temperature from the average to dry year induced decreases in annual and monthly (all months except March) runoff, and moreover, these effects were more remarkable in the wet season than those in the dry season. Due to the integrated effects of changing land use and climate conditions, the annual runoff increased (decreased) by 70.1 mm (25.2 mm) or 197.4% (71.0%) from the average to wet (dry) year. In conclusion, climate conditions, especially precipitation, played an important role in runoff variations while land use change was secondary over the study area, and furthermore, the effects of changes in land use and/or climate conditions on monthly runoff were larger in the wet season. Copyright © 2012 John Wiley & Sons, Ltd.     

On the ability of large-scale hydrological models to simulate land use and land cover change impacts in Amazonian basins

ABSTRACT

The MHD-INPE model was applied in the Ji-Parana Basin, a 30 000 km² catchment located in the southwest of the Amazon Basin which has lost more than 50% of its forest since the 1980s, to simulate land use and land cover change impacts on runoff generation process and how they are related to basin topography. Simulation results agree with observational studies in the sense that fast response processes are significant in sub-basins with steep slopes while in basins with gentle topography, the impacts are most visible in slow-response hydrological processes. On the other hand, the model is not able to capture the dependence of LUCC impacts on spatial scales. These discrepancies are probably associated with limitations in the spatial representation of heterogeneities within the model, which become more relevant at larger scales. We also tested the hypothesis that secondary forest growth should be able to compensate the decrease in evapotranspiration due to forest–cropland or forest–grassland conversion at a regional scale. Results showed that despite the small fraction of secondary forest estimated on the basin, the higher evapotranspiration efficiency of this type of forest counterbalances a large fraction of the LUCC impacts on evapotranspiration. This result suggests that enhanced transpiration due to secondary forest could explain, at least in part, the lack of clear LUCC signals in discharge series at larger scales.

EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR T. Wagener     

Using the SWAT model to assess impacts of land use changes on runoff generation in headwaters

The upstream regions of the Three Gorges Reservoir (TGR) have undergone significant changes in land use during recent years, and these changes have strongly influenced runoff generation downstream. In this study, the relationships between land use changes and corresponding hydrological responses in the Dong and Puli River basins in the upstream region of the TGR were quantified using the runoff coefficient. Empirical regression equations between the runoff coefficient and the percentage of land use types were developed for the study area using partial least squares regression (PLSR). The Soil and Water Assessment Tool was used to simulate the runoff generation processes in the two basins, and land use maps developed using Landsat Thematic Mapper images from 2000, 2005, and 2010 were compared to extract information on changes in land use. The results showed that the total area of forest and pasture decreased over the 10‐year study period, while paddy fields and upland increased in both basins. These land use changes dramatically affected hydrological processes. Evapotranspiration decreased by 2.13% and 2.41% between 2000 and 2010 in the Dong and Puli River basins, respectively, whereas quickflow, infiltration, and baseflow increased to varying degrees. The PLSR modeling results showed that upland had a negative effect on the runoff coefficient and was the most influential land use type in the study area. In contrast, a positive effect of forest on runoff generation was found in most of the regression models. Copyright © 2012 John Wiley & Sons, Ltd.     

土地利用结构与景观格局对鄱阳湖流域赣江水质的影响

于2015年1月和7月采集赣江干流及支流34个采样点水样,测定电导率、水化学离子、无机氮等水质指标.利用赣江流域2014年30 m分辨率的土地利用数据,以流域景观类型占比表征土地利用结构,景观指数表征景观格局;采用Pearson相关分析、Bioenv分析、Mantle检验与方差分解等方法分析流域土地利用结构与景观格局对赣江水质的影响.结果表明:上游Cl^-、Na⁺浓度最高,中游电导率、Cl^-、Na⁺、K⁺、Ca²⁺等水质指标最低,下游电导率、HCO₃^-、SO₄^2-、Mg²⁺、Ca²⁺、NO₃^--N等水质指标最高.居民建设用地是对水质影响最显著的单一土地利用类型.林地、水田与居民建设用地是对水质影响最显著的土地利用类型组合.平均最近邻体指数是对水质影响最显著的单一景观指数,斑块个数、斑块...     

Detecting water yield variability due to the small proportional land use and land cover changes in a watershed on the Loess Plateau,China

Soil conservation practices have been widely implemented on the Loess Plateau to reduce severe soil erosion in north‐central China over the past three decades. However, the hydrologic impacts of these practices are not well documented and understood. The objective of this study was to examine how water yield has changed after implementing soil conservation practices that resulted in changes in land use and land cover in a small agriculture‐dominated watershed, the LuErGou Watershed in Tianshui City, Gansu Province, China. We collected 23 years of hydro‐meteorological data along with three land use surveys of 1982, 1989, and 2000. The land use survey in 2000 suggested that the soil conservation efforts resulted in a 16·6%, 4%, and 16% increase in area of grassland, forested land, and terraces respectively over the two periods from 1982 to 1988 (baseline) and 1989 to 2003 (soil conservation measures implemented). Rainfall–runoff regression models developed for both time periods at the annual and monthly time steps were used to examine the significance of change in water yield in the second time period. The averaged annual run‐off coefficient over 1989–2003 did not change significantly (at the α = 0·05 level) as compared to that in the period 1982–1988. However, we found that soil conservation practices that included re‐vegetation and terracing reduced water yield during wet periods. This study highlights the importance of the precipitation regime in regulating hydrologic effects of soil conservation measures in a semi‐arid environment. We concluded that adequately evaluating the effects of land use change and soil conservation measures on water yield must consider the climatic variability under an arid environment. Copyright © 2009 John Wiley & Sons, Ltd.     

Streamflow regimes of the Yanhe River under climate and land use change,Loess Plateau,China

Soil and water conservation measures including terracing, afforestation, construction of sediment‐trapping dams, and the ‘Grain for Green Program’ have been extensively implemented in the Yanhe River watershed, of the Loess Plateau, China, over the last six decades, and have resulted in large‐scale land use and land cover changes. This study examined the trends and shifts in streamflow regime over the period of 1953–2010 and relates them to changes in land use and soil and water conservation and to the climatic factors of precipitation and air temperature. The non‐parametric Mann–Kendall test and the Pettitt test were used to identify trends and shifts in streamflow and base flow. A method based on precipitation and potential evaporation was used to evaluate the impacts of climate variability and changes in non‐climate factors changes on annual streamflow. A significant decrease (p = 0.01) in annual streamflow was observed related to a significant change point in 1996, mostly because of significant decreases in streamflow (p = 0.01) in the July to September periods in subsequent years. The annual base flow showed no significant trend from 1953 to 2010 and no change point year, mostly because there were no significant seasonal trends, except for significant decreases (p = 0.05) in the July to September periods. There was no significant trend for precipitation over the studied time period, and no change point was detected. The air temperature showed a significant increasing trend (p < 0.01), and 1986 (p < 0.01) was the change point year. The climate variability, as measured by precipitation and temperature, and non‐climate factors including land use changes and soil and water conservation were estimated to have contributed almost equally to the reduction in annual streamflow. Soil and water conservation practices, including biological measures (e.g. revegetation, planting trees and grass) and engineering measures (such as fish‐scale pits, horizontal trenches, and sediment‐trapping dams) play an important role in reduction of the conversion of rainfall to run‐off. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluating relative sensitivity of SWAT‐simulated nitrogen discharge to projected climate and land cover changes for two watersheds in North Carolina,USA

We investigated how projected changes in land cover and climate affected simulated nitrate (NO₃^?) and organic nitrogen discharge for two watersheds within the Neuse River Basin, North Carolina, USA, for years 2010–2070. We applied the Soil and Water Assessment Tool watershed model to predict nitrogen discharge using (1) atmospheric carbon dioxide (CO₂) concentrations predicted by the Intergovernmental Panel on Climate Change, (2) land cover change predicted by the Integrated Climate and Land Use Change project and (3) precipitation and temperature simulated by two statistically downscaled and bias‐corrected Global Circulation Models. We determined the sensitivity of simulated nitrogen discharge to separate changes in each treatment [(1) CO₂, (2) land cover and (3) precipitation and temperature (PT)] by comparing each treatment to a reference condition. Results showed that nitrogen discharges were most sensitive to changes in PT over the 60‐year simulation. Nitrogen discharges had similar sensitivities to the CO₂ and land cover treatments, which were only one‐tenth the influence of the PT treatment. Under the CO₂ treatment, nitrogen discharges increased with increasing ambient CO₂. NO₃^? discharge decreased with increased urbanization; however, organic nitrogen had a varied response. Under the PT treatment, there was high spatial variability in nitrogen discharges. In a single year, certain sub‐basins showed an 80% increase in nitrogen discharge relative to reference, while others showed a 400% decrease. With nitrogen discharge showing high sensitivity to PT change, we suggest that more emphasis should be placed on investigating impacts of PT on nutrient transport in the Neuse River Basin. Published 2015. This article is a U.S. Government work and is in the public domain in the USA     

A comparison of streamflow,salt and water balances in adjacent farmland and forest catchments in south‐western Victoria,Australia

A study of the hydrologic effects of catchment change from pasture to plantation was carried out in Gatum, south‐western Victoria, Australia. This study describes the hydrologic characteristics of two adjacent catchments: one with 97% grassland and the other one with 62% Eucalyptus globulus plantations. Streamflow from both catchments was intermittent during the 20‐month study period. Monthly streamflow was always greater in the pasture‐dominated catchment compared with the plantation catchment because of lower evapotranspiration in the pasture‐based catchment. This difference in streamflow was also observed even during summer 2010/2011 when precipitation was 74% above average (1954–2012) summer rainfall. Streamflow peaks in the plantation‐based catchment were smaller than in the pasture‐dominated system. Flow duration curves show differences between the pasture and plantation‐dominated catchments and affect both high‐flow and low‐flow periods. Groundwater levels fell (up to 4.4 m) in the plantation catchment during the study period but rose (up to 3.2 m) in the pasture catchment. Higher evapotranspiration in the plantation catchment resulted in falling groundwater levels and greater disconnection of the groundwater system from the stream, resulting in lower baseflow contribution to streamflow. Salt export from each catchment increases with increasing flow and is higher at the pasture catchment, mainly because of the higher flow. Reduced salt loading to streams due to tree planting is generally considered environmentally beneficial in saline areas of south‐eastern Australia, but this benefit is offset by reduced total streamflow. Copyright © 2014 John Wiley & Sons, Ltd.     

The responses of hydrological processes and sediment yield to land‐use and climate change in the Be River Catchment,Vietnam

In this study, we investigated the responses of hydrology and sediment yield with impacts of land‐use and climate change scenarios in the Be River Catchment, using the Soil and Water Assessment Tool (SWAT) hydrological model. The calibration and validation results indicated that the SWAT model is a powerful tool for simulating the impact of environmental change on hydrology and sediment yield in this catchment. The hydrologic and sediment yield responses to land‐use and climate changes were simulated based on the calibrated model. The results indicated that a 16.3% decrease in forest land is likely to increase streamflow (0.2 to 0.4%), sediment load (1.8 to 3.0%), and surface runoff (SURQ) (4.8 to 10.7%) and to decrease groundwater discharge (GW_Q) (3.5 to 7.9%). Climate change in the catchment leads to decreases in streamflow (0.7 to 6.9%) and GW_Q (3.0 to 8.4%), increase in evapotranspiration (0.5 to 2.9%), and changes in SURQ (?5.3 to 2.3%) and sediment load (?5.3 to 4.4%). The combined impacts of land‐use and climate changes decrease streamflow (2.0 to 3.9%) and GW_Q (12.3 to 14.0%), increase evapotranspiration (0.7 to 2.8%), SURQ (8.2 to 12.4%), and sediment load (2.0 to 7.9%). In general, the separate impacts of climate and land‐use changes on streamflow, sediment load, and water balance components are offset each other. However, SURQ and some component of subsurface flow are more sensitive to land‐use change than to climate change. Furthermore, the results emphasized water scarcity during the dry season and increased soil erosion during the wet season. Copyright © 2012 John Wiley & Sons, Ltd.     

Hydrological effects of climate change,groundwater withdrawal,and land use in a small Korean watershed

The effects of variability in climate and watershed (groundwater withdrawal and land use) on dry‐weather streamflows were investigated using SWAT (Soil and Water Assessment Tool). The equation to predict the total runoff (TR) using climate data was derived from simulation results for 30 years by multiple regression analysis. These may be used to estimate effects of various climate variations (precipitation during the dry period, precipitation during the previous wet period, solar radiation, and maximum temperature). For example, if daily average maximum temperature increases by 3 °C, TR during the dry period will decrease by 27·9%. Similarly, groundwater withdrawals strongly affect streamflow during the dry period. However, land use changes (increasing urbanization) within the forested watershed do not appear to significantly affect TR during the dry period. Finally, a combined equation was derived that describes the relationships between the TR during the dry period and the climate, groundwater withdrawal and urban area proportion in a small monsoon watershed. This equation will be effective to predict the water availability during the dry periods in the future since it is closely related to changes of temperature, precipitation, solar radiation, urban area ratio, and groundwater withdrawal quantity. Copyright © 2007 John Wiley & Sons, Ltd.     

A spatially distributed model for assessment of the effects of changing land use and climate on urban stream quality

While the effects of land use change in urban areas have been widely examined, the combined effects of climate and land use change on the quality of urban and urbanizing streams have received much less attention. We describe a modelling framework that is applicable to the evaluation of potential changes in urban water quality and associated hydrologic changes in response to ongoing climate and landscape alteration. The grid‐based spatially distributed model, Distributed Hydrology Soil Vegetation Model‐Water Quality (DHSVM‐WQ), is an outgrowth of DHSVM that incorporates modules for assessing hydrology and water quality in urbanized watersheds at a high‐spatial and high‐temporal resolution. DHSVM‐WQ simulates surface run‐off quality and in‐stream processes that control the transport of non‐point source pollutants into urban streams. We configure DHSVM‐WQ for three partially urbanized catchments in the Puget Sound region to evaluate the water quality responses to current conditions and projected changes in climate and/or land use over the next century. Here, we focus on total suspended solids (TSS) and total phosphorus (TP) from non‐point sources (run‐off), as well as stream temperature. The projection of future land use is characterized by a combination of densification in existing urban or partially urban areas and expansion of the urban footprint. The climate change scenarios consist of individual and concurrent changes in temperature and precipitation. Future precipitation is projected to increase in winter and decrease in summer, while future temperature is projected to increase throughout the year. Our results show that urbanization has a much greater effect than climate change on both the magnitude and seasonal variability of streamflow, TSS and TP loads largely because of substantially increased streamflow and particularly winter flow peaks. Water temperature is more sensitive to climate warming scenarios than to urbanization and precipitation changes. Future urbanization and climate change together are predicted to significantly increase annual mean streamflow (up to 55%), water temperature (up to 1.9 °C), TSS load (up to 182%) and TP load (up to 74%). Copyright © 2016 John Wiley & Sons, Ltd.     

An assessment of the geomorphodiversity and land use/cover change (LUCC) effects associated with landslides in Meghalaya,India

The Shillong Plateau in the Eastern Himalayas is exposed to high seismicity, neo-tectonic activity and orographic precipitation that aggravated landslides in the region by affecting hillslope processes. Landscape development is influenced by landslide phenomenon and depends upon geomorphic processes and geomorphodiversity (GmD). It is linked intimately with geomorphology, hydrology and soil type. This study uses a remote sensing and GIS-based approach to assess the spatial linkage between GmD and landslide distribution in Meghalaya (India). GmD index (GmDI) is developed using geological, morphometric and geomorphological parameters and analysed with landslide distribution. The landslide distribution considering land use/cover change (LUCC) is also examined. The result shows that the region with high-relief, valley and depression zone, mainly along the Dauki fault, have a high to a very high GmDI. About 61% of landslide localities are in zones of high GmDI, concentrated in the central and eastern parts of Meghalaya. Density analysis of the very high class (class 5) of GmD confirms the same. Most of these landslides occur in dense and light-vegetated landmasses. However, the LUCC analysis reveals a significant increase in the built area on steeper slopes (average expansion ratio of 2.30 for slopes >15°) between 2017 and 2022, indicating a rising threat of landslides in urban areas of Meghalaya. The study presents the importance of GmD in active tectonic regions with particular reference to landslide potential and recent LUCC. It can aid decision-makers in planning sustainable developments and risk mitigation strategies for landslide hazards and geoconservation.