Rainfall-Runoff Simulation by Using Distributed Instantaneous Unit Hydrograph Derived from Applying Flow Accumulation Value of Dem (original) (raw)
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The time-area approach provides a useful tool to understand runoff mechanisms and to construct hydrographs through its intuitive and inherently distributed concept. Some researchers have applied this approach to develop unit hydrographs (UH) at outlets. However, the UH concept has limitations in application due to assumptions of a uniform distribution of excess rainfall and a constant base time of the direct runoff hydrograph regardless of excess rainfall intensity. Therefore it may not be appropriate to use a UH in distributed hydrologic modeling of spatially varied excess rainfall. A direct method is presented to derive hydrographs from the distributed excess rainfall map using the time-area map (isochrone) without the assumptions of UH. In distributed watershed modeling, overland and channel routing are key components for simulating hydrographs at outlets. Numerical methods like FDM and FEM are commonly used to solve governing partial differential equations such as the Saint-Venant's equation to approximate discharge and depth of runoff in distributed modeling. However, an explicit solution scheme requires small 269-429-0300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA).
Journal of Hydrology, 2009
In this study, a GIS based simple and easily performed runoff routing approach based on travel time was developed to simulate storm runoff response process with consideration of spatial and temporal variability of runoff generation and flow routing through hillslope and river network. The watershed was discretized into grid cells, which were then classified into overland cells and channel cells through river network delineation from the DEM by use of GIS. The overland flow travel time of each overland cell was estimated by combining a steady state kinematic wave approximation with Manning's equation, the channel flow travel time of each channel cell was estimated using Manning's equation and the steady state continuity equation. The travel time from each grid cell to the watershed outlet is the sum of travel times of cells along the flow path. The direct runoff flow was determined by the sum of the volumetric flow rates from all contributing cells at each respective travel time for all time intervals. The approach was calibrated and verified to simulate eight storm runoff processes of Jiaokou Reservoir watershed, a sub-catchment of the Yongjiang River basin in southeast China using available topography, soil and land use data for the catchment. An average efficiency of 0.88 was obtained for the verification storms. Sensitivity analysis was conducted to investigate the effect of the area threshold of delineating river networks and parameter K relating channel velocity calculation on the predicted hydrograph at the basin outlet. The effects of different levels of grid size on the results were also studied, which showed that good results could be attained with a grid size of less than 200 m in this study.
A NEW HYDROLOGIC RES PONSE FUNCTION PHYSICALLY DERIVED FROM DEM AND REMOTE SENSING IMAGE
This study proposes a physically-based distributed instantaneous unit hydrograph by adopting the concept of IUH, which is derived based on physical runoff mechanism by combining DEMs, remote sensing and kinematic wave approximation. The heterogeneity of the watershed can be well represented by DEMs, remotely sensed data and kinematic wave approximation in the proposed physically-based distributed instantaneous unit hydrograph. As for ungauged area or the area with poor hydrologic record, the geomorphologic IUH proposed in the study is expected to be a reference for water resources designing and evaluation.
International Journal of Innovations in Science and Technology, 2019
The rapid urbanization and the population growth, have increased the demands of fresh water to manage various tasks from domestic to industrial scales. Various man driven sectors such as agriculture, industry and water filtration plants, require fresh water to cater the need of increasing population. Therefore, the management of available fresh water reservoirs is of great importance to save water for a sustainable future “save water save life”. Digital elevation model (DEM) is efficient to extract the drainage network, basin boundaries and to evaluate the volume of fresh water available in study site. We used Arc hydro tools in Arc GIS interface for extraction of drainage network in the study site. Flow direction and accumulation were computed according to Z-value of individual pixel available in the raster grid. A total 127 streams were extracted against 127 catchments. We observed that the catchments bearing steep slopes were incised in comparison to gentle slopes which were most...
Efficiency of the geomorphologic instantaneous unit hydrograph method in flood hydrograph simulation
CATENA, 2011
A watershed is considered as a system consisting of different interrelated hydrologic units that react to rainfall. The present research was carried out to investigate the consistency, accuracy and reliability of a geomorphologic model in comparison with Snyder, SCS, Triangle, Rosso and geomorphoclimatic unit hydrographs in determination of the shape and dimensions of the outlet runoff hydrograph in the Kasilian basin located in the Mazandaran Province of Iran. For this purpose, the first twenty one equivalent rainfall-runoff events were selected and for each, a hydrograph of outlet runoff was calculated. Then the models were compared with the observed hydrograph, for peak time and peak flow of outlet runoff. The most efficient model for estimation of the hydrograph of outlet flow for similar regions was proposed. Comparison of calculated and observed hydrographs showed that the geomorphologic model had the most direct agreement in two parameters of peak time and peak flow of direct runoff. Also, the geomorphological model had the least amounts of main relative and square error. The result also showed that the efficiency of geomorphologic model ratio for Snyder, SCS, Triangle, Rosso and geomorphoclimatic hydrographs in the study basin are 91.06, 99.11, 88.642, 48.195 and 4.944, respectively. Comparing with other models, the geomorphologic and geomorphoclimatic hydrographs are the most efficient methods to estimate flood discharge.
ISH Journal of Hydraulic Engineering, 2021
Floods are the most disastrous natural hazards, but the prediction of flood hydrographs is hindered due to the lack of Hydro-meteorological data. This paper presents an approach for flood routing of the ungauged basin using rainfall-runoff and Dynamic wave models. Specifically, the SCS-CN rainfall runoff model is employed to obtain the inflow and lateral inflow hydrographs of the ungauged subbasins, and a Modified Dynamic Wave Model is employed to anticipate the flood hydrograph at the outlet of the ungauged basins. The Modified Dynamic Wave Model for the parabolic channel (MDWMP) has been numerically solved using an implicit finite difference scheme considering both continuity and momentum equations. The method is tested in hypothetically considered ungauged Kulsi River Basin, a mountainous basin in Northeastern India, and the results obtained are compared with the observed data at the outlet of the Kulsi Basin. The approach is validated by considering four parameters RMSE, Peak flow Error, Peak time Error, and Total Volume Error. A high degree of affinity (i.e. peak flow error below 6%) was observed between the predicted outflow hydrograph and the observed hydrograph, which verified the satisfactory applicability of the developed approach to anticipate the flood hydrograph of an ungauged basin.
IIARD International Journal of Geography & Environmental Management (IJGEM), 2023
Rainfall runoff modelling is a vital and an essential paradigm in flood risk management. This research sought to determine the runoff and maximum discharge time of concentration (TC) in Uyo Urban to help facilitate adequate and proper flood risk and management plan in the area. The topographic map and 3D surface of the catchment area were generated and the rational method employed to determine the time of concentration of runoff as well as the maximum discharge while Hydrology extension in ArcGIS 10.3 was used to model the river basin from DEM and identify locations. Detailed analysis of 39 years (1977-2015) rainfall data was recorded to determine inter-annual variability, monthly distribution pattern, mean total annual rainfall, mean maximum daily rainfall and standardized anomaly index (SAI). The computed discharge was calculated. The results of the analyses indicate a total discharge of 1573.54m 3 /s and takes approximately 40 minutes of runoff time evident of prolonged rainstorms in areas like IBB Avenue as opposed to the short-lived rainfalls that causes flash floods in areas like Brook Street. This means that it takes a longer time of about 2 km to travel to the analysed site to cause flood. The study recommends the need for creation of more risk awareness and flood warning signs to further educate the people.
Journal of Applied Engineering Sciences, 2020
This research concerns about the development and application of Variable Parameter Kinematic Wave Numerical model (VPKWM) based on 1-D Saint-Venant equation, to study the behaviour of the propagation of a flood wave in Non-prismatic natural waterways in an ungauged basin. The channel slope and wetted perimeter are considered as variable because of the irregularity of the boundary of the channel and the change in magnitude of discharge. The scarcity of reliable inflow data at upstream is a serious problem for the flood routing process in an ungauged basin. In this study the inflow hydrograph and lateral inflow hydrographs are obtained using SCS-CN method as rainfall runoff model. The performance of the model assessed considering four parameters such as root mean square error (RMSE), peak discharge, peak time and total volume. The results indicated that the VPKWM for non-prismatic channel provided reasonable output compared with the observed data.
Rainfall-runoff simulation in an experimental basin using GIS methods,
2006
A GIS-based rainfall-runoff model was developed to simulate the runoff discharge at the outlet of a 15.18 km 2 gauged steep watershed that is located at the prefecture of Attica, Greece. The model's core is the time-area routing technique, which shares the assumptions of the unit hydrograph theory. This technique accounts for translation, does not account for watershed storage effects and is applicable mainly to small to midsized watersheds. GIS was used to develop the watershed cumulative travel time map that was divided into isochrones in order to generate the time-area histogram. Basic maps were the rasters of digital elevation model and landuse that were processed to derive the rasters of slope, flow direction, flow accumulation and roughness coefficient. The model was calibrated and validated using the observed rainfall-runoff data from thirty storm events. Two simulated hydrographs were calculated for each storm event, using the watershed time-area histogram and two temporal distributions of excess rainfall, estimated by the SCS and the Phi-Index methods. The simulated values of peak flow rate and time to peak were compared with the observed values, via statistical methods. A sensitivity analysis indicated the effect of various parameters on the simulated hydrographs.
Use of Digital Elevation Model to compute Storm Water Drainage Network
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY, 2014
Often planners and engineers are faced with various options and questions in storm drainage network design e.g. topography, flow pattern, direction and therefore size of drain or scenario after a road, airfield or building has been constructed. In most instances planning without drainage in mind has caused failure or extensive damage to property including the storm water drains which channel the water away. With the advent of GIS tools this problem can be averted. The Bhimrad area of surat city (Gujrat, India) had no storm drainage network for persistent flooding. This paper describes a method of assessing the effectiveness of storm drainage networks by a Digital Elevation Model (DEM). The DEM was generated from .dwg contour map and the data imported into ArcGIS, The 141.91hactor basin was then delineated into sub-catchments using ArcGIS Hydro extension tools. Also to derive impervious land cover, arial image of study area (Bhimrad) was accessed through ArcMap’s built-in base map function. The roads, buildings, canal, creek, water body existing land use were obtained by digitizing arial image. By overlaying the natural flow lines derived from the DEM with the reconstructed physical drains a comparison of the flow direction and the orientation of the drains was achieved. It is particularly useful for new areas where development is being contemplated. Keywords: Storm Drainage, Digital