scholarly journals Stream Discharge Response to Climate Change and Land Use Change in Tamor Basin, Nepal

2018 ◽  
Vol 5 (2) ◽  
pp. 50-62
Author(s):  
K.C. Sumitra ◽  
R.P. Shrestha ◽  
S. Shrestha

Climate change and land use change are two major issues that need to be addressed for sustainable land and water resource management. These are major factors influencing discharge in monsoon dominated basin. This study aims to quantitatively assess the impact of climate change and land use change on future discharge of the Tamor basin in Nepal. Result from the study indicated maximum temperature will reach to 40.63°C in 2030s, 40.63°C in 2060s and 45.95°C in 2090s which was 35°C in baseline period (1976-2005). Annual average precipitation was projected to change by 17.64% under RCP 4.5 and by 39.88% under RCP 8.5 till the end of the century as projected by HadGEM2. Since the basin is monsoon dominated, annual discharge was projected to increase by 12.25% under RCP 4.5 and by 32.67% under RCP 8.5 above baseline average till the end of the century. Result using HadGEM2 also shows that peak flows that used to occur in August in baseline period will shift to July except in 2030s under RCP 4.5. However, CSIRO-Mk3.6.0 projects decrease in annual precipitation and hence also discharge at the end of the century. Result from both Global Climate Models show that average monthly discharge due to climate change will change positively as well as negatively for both scenarios. Due to combined impact of land use change and climate change, annual discharge was projected to change by 16.53%, 21.28% and -4.39% under RCP 4.5 and by 38.29%, 45.64% and 13.06% under RCP 8.5 till the end of the century for conversion of forest into agricultural land, conversion of forest into barren land and conversion of barren land into forest respectively. Average annual discharge increased the most in case of conversion of forest into barren land and decreased or increased the least in case of conversion of barren land into forest. Unlike annual, seasonal response to combined impact was different. In monsoon and pre monsoon, discharge increased or decreased the least in case of conversion of forest into agricultural land and barren land while increased the least or decreased in case of conversion of barren land into forest. However, in post monsoon and winter, discharge decreased the least or increased the most in case of conversion of barren land into forest but discharge decreased the most or increased the least in case of conversion of forest into agricultural land and barren land.

2021 ◽  
Author(s):  
David Bysouth ◽  
Merritt Turetsky ◽  
Andrew Spring

<p>Climate change is causing rapid warming at northern high latitudes and disproportionately affecting ecosystem services that northern communities rely upon. In Canada’s Northwest Territories (NWT), climate change is impacting the access and availability of traditional foods that are critical for community health and well-being. With climate change potentially expanding the envelope of suitable agricultural land northward, many communities in the NWT are evaluating including agriculture in their food systems. However, the conversion of boreal forest to agriculture may degrade the carbon rich soils that characterize the region, resulting in large carbon losses to the atmosphere and the depletion of existing ecosystem services associated with the accumulation of soil organic matter. Here, we first summarize the results of 35 publications that address land use change from boreal forest to agriculture, with the goal of understanding the magnitude and drivers of carbon stock changes with time-since-land use change. Results from the literature synthesis show that conversion of boreal forest to agriculture can result in up to ~57% of existing soil carbon stocks being lost 30 years after land use change occurs. In addition, a three-way interaction with soil carbon, pH and time-since-land use change is observed where soils become more basic with increasing time-since-land use change, coinciding with declines in soil carbon stocks. This relationship is important when looking at the types of crops communities are interested in growing and the type of agriculture associated with cultivating these crops. Partnered communities have identified crops such as berry bushes, root vegetables, potatoes and corn as crops they are interested in growing. As berry bushes grow in acidic conditions and the other mentioned crops grow in more neutral conditions, site selection and management practices associated with growing these crops in appropriate pH environments will be important for managing soil carbon in new agricultural systems in the NWT. Secondly, we also present community scale soil data assessing variation in soil carbon stocks in relation to potential soil fertility metrics targeted to community identified crops of interest for two communities in the NWT.  We collected 192 soil cores from two communities to determine carbon stocks along gradients of potential agriculture suitability. Our field soil carbon measurements in collaboration with the partnered NWT communities show that land use conversions associated with agricultural development could translate to carbon losses ranging from 2.7-11.4 kg C/m<sup>2</sup> depending on the type of soil, agricultural suitability class, and type of land use change associated with cultivation. These results highlight the importance of managing soil carbon in northern agricultural systems and can be used to emphasize the need for new community scale data relating to agricultural land use change in boreal soils. Through the collection of this data, we hope to provide northern communities with a more robust, community scale product that will allow them to make informed land use decisions relating to the cultivation of crops and the minimization of soil carbon losses while maintaining the culturally important traditional food system.</p>


2016 ◽  
Author(s):  
Awoke D. Teshager ◽  
Philip W. Gassman ◽  
Justin T. Schoof ◽  
Silvia Secchi

Abstract. Modeling impacts of agricultural scenarios and climate change on surface water quantity and quality provides useful information for planning effective water, environmental, and land use policies. Despite the significant impacts of agriculture on water quantity and quality, limited literature exists that describes the combined impacts of agricultural land use change and climate change on future bioenergy crop yields and watershed hydrology. In this study, the Soil and Water Assessment Tool (SWAT) eco-hydrological model was used to model the combined impacts of five agricultural land use change scenarios and three downscaled climate pathways (representative concentration pathways, RCPs) that were created from an ensemble of eight atmosphere-ocean general circulation models (AOGCMs). These scenarios were implemented in a well calibrated SWAT model for the Raccoon River watershed (RRW) located in western Iowa. The scenarios were executed for the historical baseline, early-century, mid-century, and late-century periods. The results indicate that historical and more corn intensive agricultural scenarios with higher CO2 emissions consistently result in more water in the streams and greater water quality problems, especially late in the 21st century. Planting more switchgrass, on the other hand, results in less water in the streams and water quality improvements relative to the baseline. For all given agricultural landscapes simulated, all flow, sediment and nutrient outputs increase from early-to-late century periods for the RCP4.5 and RCP8.5 climate scenarios. We also find that corn and switchgrass yields are negatively impacted under RCP4.5 and RCP8.5 scenarios in the mid and late 21st century.


2012 ◽  
Vol 7 (5) ◽  
pp. 573-581 ◽  
Author(s):  
Subashisa Dutta ◽  
◽  
Shyamal Ghosh

Being the highest specific discharge river in the world, the Brahmaputra has a large floodplain area of 700 km in length in its middle reaches falling in the high flood vulnerability category. Floods generated in upland Himalayan catchments are mainly controlled by land use and land cover, storm characteristics, and vegetation dynamics. Floods propagate through a floodplain region consisting of wetlands, paddy agriculture, and wide braided river reaches with natural constraint points (nodals) that make the reaches more vulnerable to flood hazards. In this study, a macroscale distributed hydrological model was used to obtain the flood characteristics of the reaches. A hydrological model with spatially distributed input parameters and meteorological data was simulated at (1 km × 1 km) spatial grids to estimate flood hydrographs at the main river and itsmajor tributaries. Aftermodel validation, “best guess” land use change scenarios were used to estimate potential changes in flood characteristics. Results show that at the middle reaches of the Brahmaputra, peak discharge increases by a maximum of 9% for land use change scenarios. The same model with bias-corrected climatological data from a regional climate model (RCM) simulation (PRECIS) was used to obtain future changes in flood generation and its propagation through the basin in the projected climatological scenario. Changes in flood characteristics with reference to the baseline period show that the average duration of flood waves will increase from 15.2 days in the baseline period (1961-1990) to 19.3 days in the future (2071-2100). Peak discharge will increase by an average of 21% in the future in the projected climate change scenario. After statistics on changes of flood characteristics in the projected climate change scenario (2071-2100) were obtained, a 2-dimensional hydrodynamic model was used to obtain flood inundation and velocity distribution on the floodplain. Distribution of velocity and inundation depth was spatially analyzed to obtain flood hazard zones in the projected climate change scenario. Results show that spatial variation in flood hazard zones will be significantly altered in the projected climate change scenario compared to land use/land cover changes.


Author(s):  
Tran Thi Phuong ◽  
Nguyen Bich Ngoc ◽  
Nguyen Hoang Khanh Linh ◽  
Nguyen Thi Hong Mai ◽  
Huynh Van Chuong

The phenomenon of prolonged drought as one of the consequences of climate change has significantly affected the agricultural production of rural communities in both mountainous and plain areas of Vietnam. This study, using standardized precipitation index (SPI) combining with the space technologies of Geographical Information Systems (GIS) and Remote Sensing (RS) to simulate and forecast the effects of drought on agricultural land use in Bac Tra My district, Quang Nam province. The data was set up for two scenarios of RCP 4.5 and RCP 8.5 in Bac Tra My district of Quang Nam province. Simultaneously, the research has also applied the focus group discussion, in-depth interview and field survey for data cross-checking to ensure highly reliable predictions. The research result has addressed four levels of drought, including normal, mild, moderate and severe drought appearing in the Summer-Autumn crop in the period 2016 – 2035 of the district. In which, severe drought will appear on large scale for both scenarios of RCP 4.5 and RCP 8.5 for 5 types of agricultural land use including paddy, annual crop, perennial, afforestation and aquacultural land. From these findings, the local authorities can consider and apply the adaptation and mitigation measures to climate change in agricultural land use planning.


2021 ◽  
Author(s):  
Karina Winkler ◽  
Richard Fuchs ◽  
Mark Rounsevell ◽  
Martin Herold

<p>Land use change is a major contributor to greenhouse gas emissions and biodiversity loss and, hence, a key topic for current sustainability debates and climate change mitigation. To understand its impacts, accurate data of global land use change and an assessment of its extent, dynamics, causes and interrelations are crucial. However, although numerous observational data is publicly available (e.g. from remote sensing), the processes and drivers of land use change are not yet fully understood. In particular, current global-scale land change assessments still lack either temporal consistency, spatial explicitness or thematic detail. <br>Here, we analyse the patterns of global land use change and its underlying drivers based on our novel high-resolution (~1x1 km) dataset of global land use/cover (LULC) change from 1960-2019, HILDA+ (Historic Land Dynamics Assessment+). The data harmonises multiple Earth Observation products and FAO land use statistics. It covers all transitions between six major LULC categories (urban areas, cropland, pasture/rangeland, forest, unmanaged grass-/shrubland and no/sparse vegetation).<br>On this basis, we show (1) a classification of global LULC transitions into major processes of land use change, (2) a quantification of their spatiotemporal patterns and (3) an identification of their major socioeconomic and environmental drivers across the globe. By using temporal cross-correlation, we study the influence of selected drivers on processes such as agricultural land abandonment, deforestation, forest degradation or urbanisation.<br>With this, we are able to map the patterns and drivers of global land use change at unprecedented resolution and compare them for different world regions. Giving new data-driven and quantitative insights into a largely untouched field, we identify tele-coupled globalisation patterns and climate change as important influencing factors for land use dynamics. Learning from the recent past, understanding how socio-economic and environmental factors affect the way humans use the land surface is essential for estimating future impacts of land use change and implementing measures of climate mitigation and sustainable land use policies.</p>


Author(s):  
Wenting Li ◽  
Xiaoli Yang ◽  
Liliang Ren ◽  
Qianguo Lin ◽  
Xiong Zhou ◽  
...  

Abstract The response of blue and green water to climate and land-use change in the Ganjiang River Basin (GRB) is evaluated, via the SWAT model that combines three scenarios (the land-use/land-cover (LULC), climate change, and integrated climate and LULC change scenarios) in the 2040s (2031–2050) and 2060s (2051–2070). The results indicate that, for the GRB, cropland, woodland, and grassland show a decreasing trend, while build-up and water areas show an increasing trend in terms of future land-use change. The climatic conditions projected using NORESM1-M model data under the RCP4.5 and RCP8.5 scenarios suggest, respectively, increases in precipitation (31.17 and 27.24 mm), maximum temperature (2.25 and 2.69 °C), and minimum temperature (1.96 and 2.58 °C). Under climate change conditions, blue water is estimated to decrease by up to 16.89 and 21.4 mm under RCP4.5 and RCP8.5, while green water is estimated to increase up to 19.14 and 20.22 mm, respectively. Under the LULC changes, blue water is projected to increase by up to 5.50 and 7.57 mm, while green water shows decreases of 4.05 and 7.80 mm for the LULC2035 and LULC2055 scenarios, respectively. Under the four combined LULC and climate change conditions (RCP4.5_2040s, RCP4.5_2060s, RCP8.5_2040s, and RCP8.5_2060s), blue water tends to decrease by 0.67, 7.47, 7.28, and 9.99 mm, while green water increases by 19.24, 20.8, 13.87, and 22.30 mm. The influence of climate variation on blue and green water resources is comparatively higher than that of the integrated impacts of climate and land-use changes. The results of this study offer a scientific reference for the water resources management and planning department responsible for scheduling water resource management plan in the GRB.


2020 ◽  
Author(s):  
Stanley Chasia ◽  
Luke Olang ◽  
Lewis Sitoki ◽  
Mathew Hernnergger

<p>Changes in land use/cover are among the most important anthropogenic transformation on the physical environment affecting proper functioning of the earth system. Hitherto, land characterization has often been studied using archived satellite data products to understandd trends in space and time. However, due to future uncertainties in land use change in developing countries and the associated impacts on the physical environment, there is need to model these changes at a local scale. A modelling framework to simulate empirically quantified relations between land use and its driving factors was used in the Sio-Malaba-Malakisi catchment between Kenya and Uganda. Changes for the catchment were simulated for a period of 30 years (2017 – 2047) using model parameters that define location characteristics, spatial policies, area restrictions, land use demand and conversion elasticity settings. Elevation, slope, population density, soil organic carbon, soil CEC and precipitation were potential factors selected to evaluate the suitability of devoting a grid cell to a land use type using a stepwise regression model. The scenarios evaluated include first growth, slow growth and an urbanization scenario. The high ROC value in all statistical tests (>0.72) indicated that the spatial distribution of some land use types in the basin could be explained by the selected driving variables. In a fast growth scenario (under policy restriction), areas under open soil and shrubland would be converted to cropland when demand for cash crop goes up in the region. Areas under open trees and marshland outside protected zones, would be converted to agricultural land while barren land with rock outcrops would remain largely unchanged over the period. In a slow growth scenario, expansion of the area under cropland would follow historical trend at 1.25% growth per annum. Marshland areas unsuitable for agricultural expansion are projected to remain the same. In an urbanization scenario, built-up areas would increase steadily at >1% per annum especially in areas earmarked for infrastructural development. In all the scenarios explored, topography, precipitation, soil characteristics and population density were identified as the key drivers of land use change. Results of this study would enhance the understanding of the complexities in projecting future land cover changes and provide baseline data for supporting ongoing soil and land management programs in a data scarce area.</p><p><strong>Key words:</strong> Land use change; CLUE-S model; Scenario analysis; Sio-Malaba-Malakisi catchment; Transboundary basin</p>


Sign in / Sign up

Export Citation Format

Share Document