scholarly journals Modeling the impact of land use changes on river flows in Arror watershed, Elgeyo Marakwet County, Kenya

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.

Author(s):  
Allison Neil

Soil properties are strongly influenced by the composition of the surrounding vegetation. We investigated soil properties of three ecosystems; a coniferous forest, a deciduous forest and an agricultural grassland, to determine the impact of land use change on soil properties. Disturbances such as deforestation followed by cultivation can severely alter soil properties, including losses of soil carbon. We collected nine 40 cm cores from three ecosystem types on the Roebuck Farm, north of Perth Village, Ontario, Canada. Dominant species in each ecosystem included hemlock and white pine in the coniferous forest; sugar maple, birch and beech in the deciduous forest; grasses, legumes and herbs in the grassland. Soil pH varied little between the three ecosystems and over depth. Soils under grassland vegetation had the highest bulk density, especially near the surface. The forest sites showed higher cation exchange capacity and soil moisture than the grassland; these differences largely resulted from higher organic matter levels in the surface forest soils. Vertical distribution of organic matter varied greatly amongst the three ecosystems. In the forest, more of the organic matter was located near the surface, while in the grassland organic matter concentrations varied little with depth. The results suggest that changes in land cover and land use alters litter inputs and nutrient cycling rates, modifying soil physical and chemical properties. Our results further suggest that conversion of forest into agricultural land in this area can lead to a decline in soil carbon storage.


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 ◽  
Vol 23 (09) ◽  
pp. 381-390
Author(s):  
M.Suguna Devakumari ◽  
◽  
S. Carolin Jeeva ◽  
R.Susan Poonguzhali ◽  
◽  
...  

Due to deforestation, urbanization and land use changes, the Nilgiris district of Tamil Nadu has been impacted by climate variation. This study was carried out to explore the impact of the land use changes in Nilgiris District from 2011 to 2017using remote sensing images acquired from Landsat 7. Temperature and rainfall data of the study area were also obtained from IMD Pune. The results show that the current trend of decreasing forest area and increasing agricultural land, and the area also experienced a temperature increase of 0.4 ◦C between 2011 and 2017. This study is crucial for land planners and environmentalists to understand the impacts of land use change on the climate in Nilgiris District.


1999 ◽  
Vol 40 (2) ◽  
pp. 1-10 ◽  
Author(s):  
R. Meissner ◽  
J. Seeger ◽  
H. Rupp ◽  
H. Balla

To study and predict environmental impacts of land use changes on water quality we conducted different types of lysimeter experiments. All of them are linked to representative experimental catchment areas in the field. This allows the verification and extrapolation of lysimeter results. The objective of this paper is to discuss a strategy for using and scaling-up of lysimeter results to a field and catchment scale. It will be shown that the N-loss determined with lysimeters falls within the variation of N-balance based model calculations, and also within ground water recharge rates calculated with models commonly used in hydrology. Extrapolation of lysimeter data to a catchment with similar soils provides a reliable basis for estimating the N-leaching caused by a change in agricultural land use. On the basis of the N-loss from the soil and the N-load of the stream, the calculations show that an increase in the proportion of one year rotation fallow from 10 to 25% results in nearly a 10% increase in the N-load of the stream. However, from the point of view of protecting drinking water quality, rotation fallow for one year is not recommended because of the resulting intensified leaching of nitrates.


Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1930
Author(s):  
Daniel Castro-López ◽  
Pablo Rodríguez-Lozano ◽  
Rebeca Arias-Real ◽  
Víctor Guerra-Cobián ◽  
Narcís Prat

The Earth’s freshwater ecosystems are currently under threat, particularly in developing countries. In Mexico, intensive land use and inadequate monitoring policies have resulted in the severe degradation of the country’s freshwater ecosystems. This study assesses how the macroinvertebrate communities in the Pesquería River, located in Northeastern Mexico, are affected by riparian land use, in order to determine their potential use as bioindicators to evaluate the macroinvertebrate integrity of the Pesquería River. First, we characterized the land use cover in the riparian channel. Second, we sampled 16 sites for benthic macroinvertebrates along the main channel during the wet and dry seasons. Third, we evaluated the influence of the riparian channel land use on the macroinvertebrate community using 42 different biological metrics. The land use characterization depicted a riparian channel mainly influenced by agricultural and urban land use. Eighty-one invertebrate taxa were identified during the study. Permutational analysis of the variance analysis confirmed significant differences across the different land use classes and the macroinvertebrate community composition while no differences were found between seasons. The indicator species analysis revealed 31 representative taxa for natural land use, 1 for urban, and 4 for agricultural land use. Our modelling analysis showed that 28 of the 42 biological metrics tested responded significantly to land use disturbances, confirming the impact of land use changes on the Pesquería River’s macroinvertebrate communities and suggesting that these metrics may have a use as bioindicators. Finally, this study may provide significant biological information for further studies in similar conditions.


2015 ◽  
Vol 17 (4) ◽  
pp. 870-881 ◽  

<div> <p>In this study, we investigated the separate and combined impacts of climate and land-use changes on hydrological response in the Central Highlands of Vietnam during the period 1981-2009. The Mann-Kendall and Pettit tests were applied to detect the trends in the hydro-meteorological data. The Soil and Water Assessment Tool (SWAT) was setup in the region, and evaluation based on daily data highlights the models adequacy. From this, the responses of hydrology to climate variability and land-use changes were considered. Overall, variability in climate seems to strongly drive the variability in the hydrological response in comparison to alternations in the hydrological regime due to land-use change during the period 1981-2009. The results indicate that land-use change had a minor impact on the annual flow (0.4% reduction), whilst the impact from climate variability had been more significant (13.5% change). Under the impact of coupled climate variability and land-use change, the annual streamflow increased by 13.1%.</p> </div> <p>&nbsp;</p>


Author(s):  
J. Y. G. Dos Santos ◽  
R. M. Da Silva ◽  
J. G. Carvalho Neto ◽  
S. M. G. L. Montenegro ◽  
C. A. G. Santos ◽  
...  

Abstract. This study aims to assess the impact of the land-use changes between the periods 1967−1974 and 1997−2008 on the streamflow of Tapacurá catchment (northeastern Brazil) using the Soil and Water Assessment Tool (SWAT) model. The results show that the most sensitive parameters were the baseflow, Manning factor, time of concentration and soil evaporation compensation factor, which affect the catchment hydrology. The model calibration and validation were performed on a monthly basis, and the streamflow simulation showed a good level of accuracy for both periods. The obtained R2 and Nash-Sutcliffe Efficiency values for each period were respectively 0.82 and 0.81 for 1967−1974, and 0.93 and 0.92 for the period 1997−2008. The evaluation of the SWAT model response to the land cover has shown that the mean monthly flow, during the rainy seasons for 1967−1974, decreased when compared to 1997−2008.


2021 ◽  
Vol 325 ◽  
pp. 07001
Author(s):  
Utia Kafafa ◽  
Rika Harini

The National Southern Cross Road Route well known as Jalan Jalur Lintas Selatan (JJLS) in Indonesia. The segment which crosses Bantul Regency has 16.65 km long. The development of JJLS will have various kinds of impacts on the community around the road infrastructure. This study wants to know how the impact of the development that saw from the spatial dynamics of land-use change. The study area is located in Poncosari, Gadingsari, Srigading, Tirtohargo, and Parangtritis Village. We process the data using the map overlay technique then analyze it with quantitative descriptive. The results of this study are the development of JJLS in Bantul Regency has not significantly affected the land-use changes. It is evident from the location of the land-use change which is far from the road and tends to be disheveled. The Land-use changes that occur do not form a specific pattern such as the pattern of conversion of agricultural land into non-agricultural land. The less significant changes in land use are caused by the condition of the JJLS which is not yet fully connected. Moreover, the status of land ownership around JJLS is Sultan Ground so a special permit is needed if the community wants to use the land.


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