scholarly journals Potential Impacts of Land Use Changes on Water Resources in a Tropical Headwater Catchment

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3249
Author(s):  
Magda Stella de Melo Martins ◽  
Carlos Alberto Valera ◽  
Marcelo Zanata ◽  
Regina Maria Bessa Santos ◽  
Vera Lúcia Abdala ◽  
...  

The main objective of this study was to investigate the relationships between land use and future scenarios of land changes on water runoff and groundwater storage in an Environmental Protection Area (EPAs) watershed. The methodology was based on the application of the Soil and Water Assessment Tool (SWAT) hydrological modelling to investigate flow simulations in current land use and in two future scenarios (forest and pasture). The performance of goodness-of-fit indicators in the calibration (NSE = 0.82, R2 = 0.85, PBIAS = 11.9% and RSR = 0.42) and validation (NSE = 0.70, R2 = 0.72, PBIAS = −4% and RSR = 0.55) was classified as good and very good, respectively. The model accurately reproduced the inter-annual distribution of rainfall. The spatial distribution of average annual surface flow, lateral flow, and groundwater flow were different between sub-basins. The future scenario on land use change to forest (FRSE) and pasture (PAST) differed during the year, with greater changes on rainy and dry seasons. FRSE increase of 64.5% in area led to decreased surface runoff, total runoff, and soil water; and increased lateral flow, groundwater, and evapotranspiration. The effect of the natural vegetation cover on soil moisture content is still unclear. The hydrological model indicated the main areas of optimal spatial water flow. Considering economic values, those areas should encourage the development of government policies based on incentive platforms that can improve environmental soil and water sustainability by establishing payment for environmental services (PES).

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1464 ◽  
Author(s):  
Regina Maria Bessa Santos ◽  
Luís Filipe Sanches Fernandes ◽  
Rui Manuel Vitor Cortes ◽  
Fernando António Leal Pacheco

The study area used for this study was the Sabor river basin (located in the Northeast of Portugal), which is composed mostly for agroforestry. The objectives were to analyze the spatiotemporal dynamics of hydrological services that occurred due to land use changes between 1990 and 2008 and to consider two scenarios for the year 2045. The scenarios were, firstly, afforestation projection, proposed by the Regional Plan for Forest Management, and secondly, wildfires that will affect 32% of the basin area. In this work, SWAT (Soil and Water Assessment Tool) was used to simulate the provision of hydrological services, namely water quantity, being calibrated for daily discharge. The calibration and validation showed a good agreement for discharge with coefficients of determination of 0.63 and 0.8 respectively. The land use changes and the afforestation scenario showed decreases in water yield, surface flow, and groundwater flow and increases in evapotranspiration and lateral flow. The wildfire scenario, contrary to the afforestation scenario, showed an increase in surface flow and a decrease in lateral flow. The Land Use and Land Cover (LULC) changes in 2000 and 2006 showed average decreases in the water yield of 91 and 52 mm·year−1, respectively. The decrease in water yield was greater in the afforestation scenario than in the wildfires scenario mainly in winter months. In the afforestation scenario, the large decrease varied between 28 hm3·year−1 in October and 62 hm3·year−1 in January, while in the wildfires scenario, the decrease was somewhat smaller, varying between 15 hm3·year−1 in October and 49 hm3·year−1 in January.


2020 ◽  
Vol 14 (2) ◽  
pp. 154-161
Author(s):  
Diah Ainunisa ◽  
◽  
Gusfan Halik ◽  
Wiwik Yunarni Widiarti ◽  
◽  
...  

Population growth is one of the causes of land-use change that can increase runoff. Tanggul watershed is one of the watersheds which often overflows during the rainy season. This study purpose to analyze the effect of land-use changes on runoff in Tanggul watershed using SWAT (Soil and Water Assessment Tool) model. To make sure the performance of SWAT model calibration and classified by the value of NSE and R2. The result of calibration included in a good category and validation included in a very good category. This study was modeling forest land-use change in 2004-2017 to determine the effect of land-use change on runoff. The result in this model of forest land-use change can increase runoff.


2017 ◽  
Vol 12 (2) ◽  
pp. 344-353
Author(s):  
Catherine Chebet ◽  
Victor A. O. Odenyo ◽  
Emmanuel C. Kipkorir

Water scarcity has become a serious global problem. Therefore, there is an urgent need to understand land use changes in watershed areas and their impact on river flows. This study models the impact of land use changes on river flows in the Arror watershed in Elgeyo Marakwet County, Kenya. The primary study sources included remotely sensed and socio-economic data. Landsat 5 thematic mappers for 1986, 2000 and 2012 (resolution 30 m) were used. A 90 m Digital Elevation Model resolution was used to delineate the Arror watershed. Secondary data included climate, river discharge and soil data. Field surveys and questionnaires were used to collect socio-economic data. GIS was integrated with a Soil and Water Assessment Tool model to determine the impact of land use changes on water quantity. The calibration goodness of fit results for the model were 0.9 and 0.8, for EF (Nash-Sutcliffe Efficiency) and R-squared, respectively. The results show a reduction of 3.5% of deciduous forest and 11.8% of grassland, while agricultural land increased by 14.3% from 1986 to 2012. The 1986, 2000 and 2012 land uses yielded an annual average flow of 2.0, 2.5 and 1.9 m3/s respectively. Flow variation was attributed mainly to land use changes. Agroforestry and afforestation are recommended for sustainable watershed management.


2019 ◽  
Vol 35 (5) ◽  
pp. 723-731 ◽  
Author(s):  
Gurdeep Singh ◽  
Dharmendra Saraswat ◽  
Naresh Pai ◽  
Benjamin Hancock

Abstract. Standard practice of setting up Soil and Water Assessment Tool (SWAT) involves use of a single land use (LU) layer under the assumption that no change takes place in LU condition irrespective of the length of simulation period. This assumption leads to erroneous conclusions about efficacy of management practices in those watersheds where land use changes (LUCs) (e.g. agriculture to urban, forest to agriculture etc.) occur during the simulation period. To overcome this limitation, we have developed a user-friendly, web-based tool named LUU Checker that helps create a composite LU layer by integrating multiple years of LU layers available in watersheds of interest. The results show that the use of composite LU layer for hydrologic response unit (HRU) delineation in 2474-km2 L’Anguile River Watershed in Arkansas was able to capture changed LU at subbasin level by using LU data available in the year 1999 and 2006, respectively. The web-based tool is applicable for large size watersheds and is accessible to multiple users from anywhere in the world. Keywords: Land use, Web-based tool, SWAT, LUU Checker.


Hydrology ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 17 ◽  
Author(s):  
Sekela Twisa ◽  
Shija Kazumba ◽  
Mathew Kurian ◽  
Manfred F. Buchroithner

Understanding the variation in the hydrological response of a basin associated with land use changes is essential for developing management strategies for water resources. The impact of hydrological changes caused by expected land use changes may be severe for the Wami river system, given its role as a crucial area for water, providing food and livelihoods. The objective of this study is to examine the influence of land use changes on various elements of the hydrological processes of the basin. Hybrid classification, which includes unsupervised and supervised classification techniques, is used to process the images (2000 and 2016), while CA–Markov chain analysis is used to forecast and simulate the 2032 land use state. In the current study, a combined approach—including a Soil and Water Assessment Tool (SWAT) model and Partial Least Squares Regression (PLSR)—is used to explore the influences of individual land use classes on fluctuations in the hydrological components. From the study, it is evident that land use has changed across the basin since 2000 (which is expected to continue in 2032), as well as that the hydrological effects caused by land use changes were observed. It has been found that the major land use changes that affected hydrology components in the basin were expansion of cultivation land, built-up area and grassland, and decline in natural forests and woodland during the study period. These findings provide baseline information for decision-makers and stakeholders concerning land and water resources for better planning and management decisions in the basin resources’ use.


2021 ◽  
Author(s):  
Christoph Zöckler ◽  
Dominic Wodehouse ◽  
Matthias Markolf

Mangroves are globally threatened, disappearing and degraded. They are lost due to land use changes, mostly agricultural expansion and aquaculture, but also degraded by cutting by villagers and logging and timber extraction for domestic and economic purposes. Extent and conversion of mangroves can usually be estimated by applying remote sensing and modern drone technology, but the scale of degradation of mangrove habitats is not easily detected by such methods. In this paper we propose an assessment tool for a rapid evaluation on the degradation, using examples from different regions in Myanmar and Madagascar. We propose a visual and practical guide listing a range of 1–6 to identify and quantify the level of degradation. We demonstrate the application by displaying various examples from Myanmar and Madagascar and how this tool can be used for wider applications, discussing advantages scope, and limitations.


2020 ◽  
Vol 13 (2) ◽  
pp. 576
Author(s):  
Letícia Lopes Martins ◽  
Wander Araújo Martins ◽  
Jener Fernando Leite De Moraes ◽  
Mário José Pedro Júnior ◽  
Isabella Clerici De Maria

A dificuldade na gestão de recursos hídricos aliada à dinâmica do uso e ocupação do solo em bacias hidrográficas agrícolas são fatores relevantes para a conservação da água e solo. A gestão de bacias hidrográficas, bem como o monitoramento de cenários de expansão agrícola e mudança no uso do solo, podem se beneficiar de ferramentas de modelagem hidrossedimentológica, como o SWAT (Soil and Water Assessment Tool). Entretanto, para que os resultados obtidos sejam confiáveis, os modelos precisam ser calibrados. Objetivou-se, neste trabalho, calibrar e validar o modelo SWAT, para a variável vazão, tendo como base a bacia hidrográfica do Ribeirão do Pinhal, Limeira -São Paulo, que se caracteriza pela expansão da cana-de-açúcar sobre áreas citrícolas. Dados de vazão de um posto fluviométrico localizado no exutório da bacia foram utilizados para a calibração e validação, a partir de séries temporais diferentes.  Utilizou-se o software QSWAT para a simulação hidrológica e o SWAT-CUP para a calibração e validação do modelo. O modelo foi calibrado e validado resultando nos seguintes índices estatísticos NSE=0,64; PBIAS=15,2 e RSR=0,60 para calibração e NSE=0,68 PBIAS=-2,8 e RSR=0,56 para a validação. O ajuste de parâmetros do SWAT (USLE_P, USLE_C, CN2) e do calendário de operações da cana-de-açúcar em acordo com a situação real da bacia foi necessário para a calibração do modelo. Os resultados indicam que o modelo SWAT subestima as vazões extremas, no entanto, dentro de faixa aceitável. O SWAT, após a calibração, pode ser utilizado na gestão de recursos hídricos na bacia do Ribeirão do Pinhal.Hydrological calibration of the SWAT model in a watershed characterized by the expansion of sugarcane cultivationA B S T R A C TThe difficulty in water resources management combined with the dynamics of land use and occupation in agricultural watersheds are relevant factors for water and soil conservation. River basin management, as well as monitoring scenarios of agricultural expansion and land-use change, can benefit from hydrossedimentological modeling tools such as the SWAT (Soil and Water Assessment Tool). However, for the results to be reliable, the models must be calibrated. The objective of this study was to calibrate and validate the SWAT model for the flow variable, based on the Ribeirão do Pinhal watershed, Limeira-São Paulo, which is characterized by the expansion of sugarcane over citrus areas. Flow data from a fluviometric station located in the basin's outfall were used for calibration and validation from different time series. QSWAT software was used for hydrological simulation and SWAT-CUP for model calibration and validation. The model was calibrated and validated resulting in the following statistical indices NSE = 0.64; PBIAS = 15.2 and RSR = 0.60 for calibration and NSE = 0.68 PBIAS = -2.8 and RSR = 0.56 for validation. Adjustment of SWAT parameters (USLE_P, USLE_C, and CN2) and the sugarcane operation schedule according to the actual basin situation was necessary for model calibration. The results indicate that the SWAT model underestimates the extreme flow rates, however, within an acceptable range. After calibration, the SWAT can be used to manage water resources in the Ribeirão do Pinhal basin.Keywords: Hydrologic simulation; land use; flow rate.


Agrologia ◽  
2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Ruddi Soplanit ◽  
Charles Silahooy

The study was conducted to quantify the land use changes that have occurred in the watershed Batugajah and evaluate the impact of changes in land use to changes in surface flow, inter flow and base flow. The results showed that the change in land use in the watershed Batugajah of the year 1998-2010 as follows: The decline occurred from 215.70 ha forest area to forest area 58.88 ha or 28.73% decrease, increasing the wide use of residential land of 25 ha to 183.62 ha, an increase of 29.06%; vast improvement hamlet of 155, 65 ha to 221.78 ha, an increase of 12.12%. The impact of land use changes as follows: Runoff increased from 2288.35 mm to 2291.35 mm; annual runoff  increased from 2525.81 mm to 2646.70 mm; interflo) increased from 103.382 mm to 244.99 mm; Water yield increased from 210.48 mm to 220.56 mm and the base flow  dropped 141.07 mm to 110.35 mm.


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