scholarly journals Quantitative Analysis of Geomorphologic Characteristics for Surface Runoff Determination in Amala River Catchment in Kenya

Author(s):  
Samuel M. Kinyanjui ◽  
Japheth O. Onyando ◽  
Raphael M. Wambua

Hydrological response of a catchment is a function of rainfall as influenced by catchment characteristics comprising geomorphology, land cover, and management practices. In this study, the analysis mainly focused on how geomorphological characteristics influence the catchment hydrological response. Geomorphological analyses of catchment geometry, stream patterns, relief, and slope can be used to characterize the catchment features that affect the drainage network. These characteristics are catchment specific and therefore unique to provide an insight into its hydrologic response. The objective of this research was to quantitatively analyze geomorphologic characteristics; linear, areal, drainage pattern, and relief aspect, of Amala River catchment, using ArcGIS tools and infer its hydrological behavior. The morphometry of the catchment was derived from the DEM within the ArcMap environment. These parameters as well as mathematical map equations were used to derive geomorphological characteristics such as bifurcation ratio, rho coefficient, drainage density, infiltration number, form factor among others. The results show that the Amala River catchment is elongated with uniform lithology and a higher probability of delayed peak hydrographs due to longer lag time and time of concentration. The catchment exhibits a dendritic drainage pattern with an average bifurcation ratio of 4.26 which is closer to the upper bound value of 5. This indicates a reduction in peak flows and a delayed time to peak. The surface runoff yield efficiency was low and non-uniform with an average drainage density of 1.073 km/km2. The catchment was characterized by higher infiltration characteristics as compared to surface flows, this varied spatially, with sub-basins far North of the outlet having high infiltration than those near the outlet. The catchment relief was characterized as steep and therefore high stream velocity was inferred. The investigation and findings of this study on catchment geomorphology and inferred hydrologic behavior will be of great importance in catchment management, water resource planning within the catchment, and water harvesting at a spatial scale. Thus, the outcomes provide a baseline for informed water pan and water harvesting structures site.

Author(s):  
Kannan R ◽  
Venkateswaran S

GIS and Remote sensing have proved to be a resourceful tool in the explanation of drainage pattern for water resources management and its planning. The identification of morphometric characteristics based on a Geographic Information System (GIS) was carried out in the Nagavathi watershed, Dharmapuri District. The quantitative drainage morphometric parameters was carried out for the Nagavathi watershed by estimating their (a) Linear aspects like Stream number, Stream order, Stream length, Mean stream length, Stream length ratio, Bifurcation ratio, (b) Aerial aspects like Drainage density, Stream frequency, Texture Ratio, Elongation ratio, Form factor, Circularity index, Length of overflow, Constant of Channel maintenance, Drainage texture, Compactness coefficient and (c) Relief aspects like Basin relief, Relief ratio, Ruggedness number, Gradient ratio, Melton ruggedness ratio, Slope,  relative relief, Shape Factor and Leminscate.  The drainage area of Nagavithi watershed is 482 sq. Km. the main drainage patterns is dendritic to sub-dendritic drainage. The Nagavathi watershed was classified as a fifth order drainage watershed, whereas micro watershed was classified as an eight in the watershed. Stream order of the watershed was predominantly controlled by structural and lithological controls of various drainage patterns and their stream orientations were identified to evaluate the direction and controlling factors in drainage network. The drainage density in the area has been found to be low which indicates that the area possesses highly permeable soils and low relief. The bifurcation ratio varies from 0.8 to 43.1. The elongation ratio of  Microwatersheds  varies  from  0.13  to  0.43, indicates  Microwatersheds  fall  under elongated  pattern. This study would help the local people to utilize the resources for planning rainwater harvesting and watershed management.


2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Gabriel Minea

AbstractThe purpose of this paper is to identify areas with high flash-flood potential based on an evaluation of physiographic factors controlling the formation of surface runoff. The research method relies on the use of the Flash Flood Potential Index (FFPI), which incorporates physiographic characteristics from the catchment (terrain slope, profile curvature, land use and soil texture). The spatial distribution of the physiographic factors (which contribute to the creation, control and concentration within the drainage network of the overland flow) and the classified zoning of areas according to their hydrological response were achieved with GIS techniques. The results obtained show that physiographic factors on 227 sq km (29%) favor surface runoff on slopes and its localization towards the drainage network. Notably, the highest values of FFPI belong to the lower part of the catchment, where high human population density can be found, reflecting an increased vulnerability to floods and inundations of this area.


2014 ◽  
Vol 6 (2) ◽  
pp. 442-450 ◽  
Author(s):  
Vishal K. Ingle ◽  
A. K. Mishra ◽  
A. Sarangi ◽  
D. K. Singh ◽  
V. K. Seghal

The study area Tapi River catchment covers 63,922.91 Sq.Km comprising of 5 five Sub-catchments: Purna river catchment (18,473.6 sq.km) Upper Tapi catchment (10,530.3 sq. km), Middle Tapi catchment (4,997.3 sq km), Girna river catchment (10,176.9 sq.km) and lower Tapi catchment (19,282.5 sq.km.). The drainage network of 5 Sub-catchments was delineated using remote sensing data. The morphometric analysis of 5 Sub-catchments has been carried out using GIS softwares – ArcMap. The drainage network showed that the terrain exhibits dendritic to sub-dendritic drainage pattern. Stream orders ranged from sixth to seventh order. Drainage density varied between 0.39 and 0.43km/ km2and had very coarse to coarse drainage texture. The relief ratio ranged from 0.003 to 0.007. The mean bifurcation ratio varied from 4.24 to 6.10 and falls under normal basin category. The elongation ratio showed that all catchment elongated pattern. Thus, the remote sensing techniques proved to be a competent tool in morphometric analysis.


Author(s):  
M. Dhanusree ◽  
G. Bhaskaran

Aims: The paper aims to study about the river basin morphometry namely the physical, linear and aerial parameters for the basin. Study Design: The Study has been carried out with the help of Geospatial techniques and statistical formulas. Place and Duration of Study: Bharathapuzha river basin, Kerala, India between January 2018 to July 2018. Methodology: The Study of River morphometry of Bharathapuzha River basin has been done with the help of SRTM satellite data. The downloaded data has been analyzed with the help of ARC GIS Software. The morphometric analysis has been carried out by dividing the basin into nine watersheds based on Water shed Atlas of India Prepared by Soil and Land Use board of           India. Relief, Linear and areal parameters of the basin is calculated with the help of statistical formulas. Results: Based on the analysis it is noted that there is not much difference in morphometric values except in some watersheds. Watershed number 5A2B5, 5A2B6 and 5A2B7 has highest drainage density, stream frequency, relief, relief ratio, ruggedness number, stream length ratio and lowest bifurcation ratio. These watersheds are characterized by highest surface runoff and erosion. The values of form factor, circulatory ratio and elongation ratio suggests that most of the watersheds are elongated and has high basin relief. The maximum stream order frequency is observed in case of first order streams and then for second order streams. Hence it is noted that there is decrease in stream frequency as stream order increases. Conclusion: The mean bifurcation ratio of the Bharathapuza basin is 1.52 which indicates the whole basin is less effected by structural control. This present study is valuable for the erosion control, watershed management, land and water resource planning and future prospective related to runoff study.


1986 ◽  
Vol 18 (4-5) ◽  
pp. 53-61 ◽  
Author(s):  
P. B. Birch ◽  
G. G. Forbes ◽  
N. J. Schofield

Early results from monitoring runoff suggest that the programme to reduce application of superphosphate to farmlands in surrounding catchments has been successful in reducing input of phosphorus to the eutrophic Peel-Harvey estuary. In the estuary this phosphorus fertilizes algae which grow in abundance and accumulate and pollute once clean beaches. The success of the programme has been judged from application of an empirical statistical model, which was derived from 6 years of data from the Harvey Estuary catchment prior to a major change in fertilizer practices in 1984. The model relates concentration of phosphorus with rate of flow and time of year. High phosphorus concentrations were associated with high flow rates and with flows early in the high runoff season (May-July). The model predicted that the distribution of flows in 1984 should have resulted in a flow-weighted concentration of phosphorus near the long-term average; the observed concentration was 25% below the long-term average. This means that the amount of phosphorus discharged into the Harvey Estuary could have been about 2 5% less than expected from the volume of runoff which occurred. However several more years of data are required to confirm this trend.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 704
Author(s):  
Hussein Al-Ghobari ◽  
Ahmed Z. Dewidar

An increasing scarcity of water, as well as rapid global climate change, requires more effective water conservation alternatives. One promising alternative is rainwater harvesting (RWH). Nevertheless, the evaluation of RWH potential together with the selection of appropriate sites for RWH structures is significantly difficult for the water managers. This study deals with this difficulty by identifying RWH potential areas and sites for RWH structures utilizing geospatial and multi-criteria decision analysis (MCDA) techniques. The conventional data and remote sensing data were employed to set up needed thematic layers using ArcGIS software. The soil conservation service curve number (SCS-CN) method was used to determine surface runoff, centered on which yearly runoff potential map was produced in the ArcGIS environment. Thematic layers such as drainage density, slope, land use/cover, and runoff were allotted appropriate weights to produced RWH potential areas and zones appropriate for RWH structures maps of the study location. Results analysis revealed that the outcomes of the spatial allocation of yearly surface runoff depth ranging from 83 to 295 mm. Moreover, RWH potential areas results showed that the study areas can be categorized into three RWH potential areas: (a) low suitability, (b) medium suitability, and (c) high suitability. Nearly 40% of the watershed zone falls within medium and high suitability RWH potential areas. It is deduced that the integrated MCDA and geospatial techniques provide a valuable and formidable resource for the strategizing of RWH within the study zones.


Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1636
Author(s):  
Thanh N. Le ◽  
Duy X. Tran ◽  
Thuong V. Tran ◽  
Sangay Gyeltshen ◽  
Tan V. Lam ◽  
...  

Saltwater intrusion risk assessment is a foundational step for preventing and controlling salinization in coastal regions. The Vietnamese Mekong Delta (VMD) is highly affected by drought and salinization threats, especially severe under the impacts of global climate change and the rapid development of an upstream hydropower dam system. This study aimed to apply a modified DRASTIC model, which combines the generic DRASTIC model with hydrological and anthropogenic factors (i.e., river catchment and land use), to examine seawater intrusion vulnerability in the soil-water-bearing layer in the Ben Tre province, located in the VMD. One hundred and fifty hand-auger samples for total dissolved solids (TDS) measurements, one of the reflected salinity parameters, were used to validate the results obtained with both the DRASTIC and modified DRASTIC models. The spatial analysis tools in the ArcGIS software (i.e., Kriging and data classification tools) were used to interpolate, classify, and map the input factors and salinization susceptibility in the study area. The results show that the vulnerability index values obtained from the DRASTIC and modified DRASTIC models were 36–128 and 55–163, respectively. The vulnerable indices increased from inland districts to coastal areas. The Ba Tri and Binh Dai districts were recorded as having very high vulnerability to salinization, while the Chau Thanh and Cho Lach districts were at a low vulnerability level. From the comparative analysis of the two models, it is obvious that the modified DRASTIC model with the inclusion of a river or canal network and agricultural practices factors enables better performance than the generic DRASTIC model. This enhancement is explained by the significant impact of anthropogenic activities on the salinization of soil water content. This study’s results can be used as scientific implications for planners and decision-makers in river catchment and land-use management practices.


Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1490 ◽  
Author(s):  
Amy Steimke ◽  
Bangshuai Han ◽  
Jodi Brandt ◽  
Alejandro Flores

Hydrologic scientists and water resource managers often focus on different facets of flow regimes in changing climates. The objective of this work is to examine potential hydrological changes in the Upper Boise River Basin, Idaho, USA in the context of biophysical variables and their impacts a key variable governing administration of water resources in the region in an integrated way. This snowmelt-dominated, mountainous watershed supplies water to a semi-arid, agriculturally intensive, but rapidly urbanizing, region. Using the Envision integrated modeling framework, we created a hydrological model to simulate hydrological response to the year 2100 using six alternative future climate trajectories. Annual discharge increased from historical values by 6–24% across all simulations (with an average 13% increase), reflecting an increase in precipitation in the climate projections. Discharge peaked 4–33 days earlier and streamflow center of timing occurred 4–17 days earlier by midcentury. Examining changes in the date junior water rights holders begin to be curtailed regionally (the Day of Allocation), we found that the it occurs at least 14 days earlier by 2100 across all simulations, with one suggesting it could occur over a month earlier. These results suggest that current methods and policies of water rights accounting and management may need to be revised moving into the future.


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