scholarly journals Assessment of the Impact of Changing Land Use and land Cover on the Peak Discharges of a Tropical Watershed: A Study of the Davao River Basin

2021 ◽  
Vol 822 (1) ◽  
pp. 012018
Author(s):  
F D Santos ◽  
K A D Sablan ◽  
C E Gonzales ◽  
W E Gonzales
Hydrology ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 2 ◽  
Author(s):  
Kinati Chimdessa ◽  
Shoeb Quraishi ◽  
Asfaw Kebede ◽  
Tena Alamirew

In the Didessa river basin, which is found in Ethiopia, the human population number is increasing at an alarming rate. The conversion of forests, shrub and grasslands into cropland has increased in parallel with the population increase. The land use/land cover change (LULCC) that has been undertaken in the river basin combined with climate change may have affected the Didessa river flow and soil loss. Therefore, this study was designed to assess the impact of LULCC on the Didessa river flow and soil loss under historical and future climates. Land use/land cover (LULC) of the years 1986, 2001 and 2015 were independently combined with the historical climate to assess their individual impacts on river flow and soil loss. Further, the impact of future climates under Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5) scenarios on river flow and soil loss was assessed by combining the pathways with the 2015 LULC. A physically based Soil and Water Assessment Tool (SWAT2012) model in the ArcGIS 10.4.1 interface was used to realize the purpose. Results of the study revealed that LULCC that occurred between 1986 and 2015 resulted in increased average sediment yield by 20.9 t ha−1 yr−1. Climate change under RCP2.6, RCP4.5 and RCP8.5 combined with 2015 LULC increased annual average soil losses by 31.3, 50.9 and 83.5 t ha−1 yr−1 compared with the 2015 LULC under historical climate data. It was also found that 13.4%, 47.1% and 87.0% of the total area may experience high soil loss under RCP2.6, RCP4.5 and RCP8.5, respectively. Annual soil losses of five top-priority sub catchments range from 62.8 to 57.7 per hectare. Nash Stuncliffe Simulation efficiency (NSE) and R2 values during model calibration and validation indicated good agreement between observed and simulated values both for flow and sediment yield.


2021 ◽  
Vol 16 (3) ◽  
pp. 662-664
Author(s):  
Sabu Joseph ◽  
Rahul R ◽  
Sukanya S

The changes in the pattern of land use and land cover (LU/LC) have remarkable consequences on ecosystem functioning and natural resources dynamics. The present study analyzes the spatial pattern of LU/LC change detection along the Killiar River Basin (KRB), a major tributary of Karamana river in Thiruvananthapuram district, Kerala (India), over a period of 64 years (1957-2021) through Remote Sensing and GIS approach. The rationale of the study is to identify and classify LU/LC changes in KRB using the Survey of India (SOI) toposheet (1:50,000) of 1957, LISS-III imagery of 2005, Landsat 8 OLI & TIRS imagery of 2021 and further to scrutinize the impact of LU/LC conversion on Soil Organic Carbon stock in the study area. Five major LU/LC classes, viz., agriculture land, built-up, forest, wasteland and water bodies were characterized from available data. Within the study period, built-up area and wastelands showed a substantial increase of 51.51% and 15.67% respectively. Thus, the general trend followed is the increase in built-up and wastelands area which results in the decrease of all other LU/LC classes. Based on IPCC guidelines, total soil organic carbon (SOC) stock of different land-use types was estimated and was 1292.72 Mt C in 1957, 562.65 Mt C in 2005 and it reduced to 152.86 Mt C in 2021. This decrease is mainly due to various anthropogenic activities, mainly built-up activities. This conversion for built-up is at par with the rising population, and over-exploitation of natural and agricultural resources is increasing every year.


2021 ◽  
Author(s):  
Shaini Naha ◽  
Miguel A. Rico-Ramirez ◽  
Rafael Rosolem

Abstract. The objective of this study is to assess the impacts of Land Use Land Cover change on the hydrological responses of the Mahanadi river basin, a large river basin in India. Commonly, such assessments are accomplished by using distributed hydrological models in conjunction with different land use scenarios. However, these models through their complex interactions among the model parameters to generate hydrological processes, can introduce significant uncertainties to the hydrological projections. Therefore, we seek to further understand the uncertainties associated with model parameterization in those simulated hydrological responses due to different land cover scenarios. We performed a sensitivity-guided model calibration of a physically semi-distributed model, the Variable Infiltration Capacity (VIC) within a Monte Carlo Framework to generate behavioural models for subcatchments of the Mahanadi river basin. These behavioural models are then used in conjunction with historical and future land cover scenarios from the recently released, Land use Harmonisation (LUH2) to generate hydrological predictions and related uncertainties from behavioural model parameterisation. The LUH2 dataset indicates a noticeable increase in the cropland (23.3 % cover) at the expense of forest (22.65 % cover) by the end of year 2100 compared to the baseline year, 2005. As a response, simulation results indicate a median percent increase in the extreme flows (defined as the 95th percentile or higher river flow magnitude) and mean annual flows in the range of 1.8 to 11.3 % across the subcatchments. The direct conversion of forested areas to agriculture (on the order of 30,000 km2) reduces the Leaf Area Index and which subsequently reduces the Evapotranspiration (ET) and increases surface runoff. Further, the range of behavioural hydrological predictions indicated variation in the magnitudes of extreme flows simulated for the different land cover scenarios, for instance uncertainty in far future scenario ranges from 17 to 210 cumecs across subcatchments. This study indicates that the recurrent flood events occurring in the Mahanadi river basin might be influenced by the changes in LULC at the catchment scale and suggests that model parameterisation represents an uncertainty, which should be accounted for in the land-use change impact assessment.


2020 ◽  
Author(s):  
Shaini Naha ◽  
Miguel A. Rico-Ramirez ◽  
Rafael Rosolem

Abstract. Several research studies have addressed the effects of future climate changes on the hydrological regime of Mahanadi river basin located in eastern part of India. However, studies investigating the effects of future land cover changes on hydrology are limited owing to the lack of availability of projected land cover scenarios. Our study investigates how the hydrology of Mahanadi river basin would respond to the current and future land cover scenarios under a large-scale hydrological modelling framework. Both historical and future land cover scenarios from the recently released, Land use Harmonisation (LUH2) project for CMIP6, indicates cropland and forest are the major land cover types in the basin with a noticeable increase in the cropland (23.3 %) at the expense of forest (22.65 %) by the end of year 2100 compared to the baseline year, 2005. A physically semi-distributed model, the Variable Infiltration Capacity has been set up and implemented over the Mahanadi river basin system for the time period 1990–2010. The uncertain model parameters were subjected to Sensitivity Analysis and calibrated within a Monte Carlo framework. The best set of calibrated models obtained is used in conjunction with the harmonized set of present and future land use scenarios from LUH2 at 25 km by 25 km resolution to generate an ensemble of model simulations that captures a range of plausible impacts of land cover changes on discharge and other hydrological components of the basin. Overall, model simulation results indicate an increase in the extreme flows (i.e., 95th percentile or higher) in the range of 0.12 to 21 % at multiple subcatchments within the basin. This increase can be attributed to the direct conversion of forested areas to agriculture (on the order of 30,000 km2) that has reduced the Leaf Area Index and subsequently reduces the Evapotranspiration (ET). These changes ultimately affect other water balance components at the land surface, resulting in an increase in surface runoff and baseflow, respectively.


Author(s):  
K. Venkatesh ◽  
H. Ramesh

<p><strong>Abstract.</strong> Streamflow can be affected by a number of aspects related to land use and can vary promptly as those factors change. Urbanization, deforestation, mining, agricultural practices and economic growth are some of the factors related to these land use changes which alter the stream flow. In the present study, the impact of land use land cover change (LULC) on stream flow is studied by using SWAT model for Tungabhadra river basin, located in the state of Karnataka, India. Tungabhadra river originates in the Western Ghats of Karnataka and flows towards north-east and joins the river Krishna. The land use maps of 1993, 2003 and 2018 are used for assessing the stream flow changes with respect to LULC. Calibration and validation of the model for streamflow was carried out using the SUFI-2 algorithm in SWAT-CUP for the years 1983&amp;ndash;1993 and 1994&amp;ndash;2000 respectively. Statistical parameters namely Coefficient of Determination (R<sup>2</sup>) &amp;amp; Nash–Sutcliffe (N-S) were used to assess the efficiency and performance of the SWAT model. It was found that the observed and simulated streamflow values are closely matching, which in turn projects that the model results are acceptable. The calibrated model was used for simulation of future dynamic land use scenario to assess the impact on streamflow. The results can be used for conservation of water and soil management.</p>


GeoScape ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 19-29
Author(s):  
Monoj Kumar Jaiswal ◽  
Nurul Amin

Abstract Alteration of land-use land cover pattern causes severe consequences on the hydrological system by modifying the rainfall-runoff pattern in a region. The study aimed to investigate the impact of land-use land-cover dynamics on runoff generation in different geomorphic divisions of Panchnoi River basin. The study used the Soil Conservation Service-Curve Number method to estimate runoff generation in the Panchnoi River basin in a GIS platform. This study observed that the conversion of the land-use pattern in the geomorphic zones significantly enhances runoff. The Piedmont experience highest land-use change, where 64.17 km2 forest cover lost to cropland and built-up lands, leads to a notable increase in runoff generation, i.e. from 1 076 mm (52.82% of rainfall) in 1990 to 1 467 mm (70.46% of rainfall) in 2015. The Flood plain and New alluvial plain generates high runoff in the basin as it mostly occupied by human-induced land-uses, i.e. 1 444 mm (72.72% of rainfall) and 1 360 mm (71.70% of rainfall) respectively in 1990, which increase to 1588 mm (79.20%) and 1507 mm (78.69%) runoff respectively in 2015, due to alteration of cropland to built-up lands. In the Old alluvial plain, a marginal land-use change observed resulted in moderate growth in runoff from 1 272 mm (62.35%) to 1 404 mm (66.79%). The study indicates land-use land-cover change invokes to increase runoff generation can give rise severe environmental and economic problems in the river basin, through the occurrence of flashflood and soil erosion. Highlights for public administration, management and planning: • Evaluation of the impact of land-use land cover dynamics on runoff is essential for containing flash flood and water resource management on a basin scale. • Alteration of natural land covers has severe implications in the form of flood, soil erosion, and loss of biodiversity. • Enhanced runoff due to land-use dynamics reduces groundwater recharge rate that may cause drinking water scarcity in the dry season shortly.


Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1206 ◽  
Author(s):  
Nguyen Truong ◽  
Hong Nguyen ◽  
Akihiko Kondoh

The upstream Dong Nai River Basin is located in the country’s key economic development region and its water resources are a key component of sustainable regional development. The objective of this study was to assess the impact of land use and land cover changes (LULCC) on the flow regime in this tropical forest basin using a flow–duration curve analysis that has been widely used in Japan. This study combined two different temporal and spatial scales of satellite data, Landsat and Global Inventory Modeling, and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI) to analyze LUCC. Results from the land cover classification of five Landsat images between 1973 and 2014 indicated that the forest area decreased significantly in the period of 1994 to 2005 due to population growth, leading to land conversion for agriculture. Furthermore, secular changes in the annual GIMMS-NDVI data revealed that land cover changes occurred from 1996 and a large amount of forest was lost in 1999; however, due to the rapid regrowth of secondary forest of tropical forests and the development of the crop, the vegetation recovered shortly afterwards in 2000 before decreasing again after 2004. Following large-scale deforestation, the total discharge, maximum flow, and the plentiful, ordinary, low, and small-scale runoff increased sharply and decreased thereafter because of vegetation regrowth.


2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Shpejtim Bulliqi ◽  
Leutrim Krasniqi ◽  
Florim Isufi

Based on the dialectical principle, an attempt was made to analyze in details the impact of relief on land cover and land use. To achieve this objective, the Llap river basin was chosen. The Llap river basin lies in the north-eastern part of Kosovo, which is discerned as a morphological whole with particular physical-geographic elements. Since the past, relief was a factor with direct and indirect impact on land cover and especially on land use. The essential part of the analysis was the correlation of the geomorphometric parameters (altitude and slope) with land cover and land use. For calculating these parameters, a digital elevation model of 12 m / pixel was downloaded from the Alaska Satellite Facility. On the other hand, the CORINE Land Cover 2012 data from the European Environment Agency (EEA) were used for land cover. The completion of the analysis was done in that form for each category of geomorphometric parameters was compared with land cover and land use. It is evident that relief has influenced the Llap basin, both in the extent of settlements and in the activities that human develop on this land.


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