Hydrograph Analysis Research Articles

Distribution of Flood Risk Area in Bodri Watershed of Kendal Regency

Flooding is a catastrophic phenomenon that can occur due to various factors, such as uncontrolled landuse changes, climate change, and weather anomalies, and drainage infrastructure damage. The Bodri watershed in Kendal Regency is one of the watersheds in Central Java, which is categorized as critical based on Decree No.328/Menhut-II/2009. Some of the problems in the Bodri watershed include land use that is not suitable for its designation, flooding, erosion, and landslides. This study aims to conduct spatial modeling to create flood hazard maps and flood risk level maps in the Bodri watershed. The method used is hydrograph analysis, flood modeling, potential flood hazards, and flood risk levels. Analysis of the potential for flood hazards from the spatial modeling inundation map with the input of the flood peak return period of 2 years (Q2), 5 years (Q5), and 50 years (Q50). Vulnerability analysis based on land use maps of flood hazard areas. The distribution of flood-prone areas in the Bodri watershed is in Pidodo Kulon Village, Pidodo Wetan Village, and Bangunsari Village.

A comparative evaluation of automated recession extraction methods to determine the late-time recession characteristics of karst spring hydrographs

Recession Curve Analysis is a common method to characterize karstic aquifers and their discharge dynamics. Although this technique provides crucial information on quantifying system hydrodynamic properties, the manually selected recession curves analysis is neither a practical technique to cover all candidate recession curves, nor it allows extracting the entire hydrological diversity of the recession behavior. This study aimed to comparatively evaluate the applicability of automated recession selection procedures to the late-time recession analysis of karst spring hydrograph. For the comparative evaluation of the three automated recession extraction methods (Vogel Method, Brutsaert Method, and Aksoy and Wittenberg Method), we quantified the late-time recession parameters of spring hydrographs by combining three extraction methods with four recession analysis methods (Maillet, 1905; Boussinesq, 1904; Coutagne, 1948; and Wittenberg, 1999). By applying our experimental design into the five karst springs located in Austria, we identified the possible weaknesses of the automated recession extraction procedures for the late-time recession analysis for spring hydrographs. To explore the value of the karst spring’s physicochemical data (electrical conductivity and water temperature) as a completion data for the recession curve analysis, we carried out the hydro-chemograph analysis to examine the recession time and its duration. The research provides a research direction as to how the automated recession extraction procedures for the karst spring hydrographs could be improved by the physicochemical signatures of karst springs.

Optimising the design and real-time operation of systems of distributed stormwater storages to reduce urban flooding at the catchment scale

The impact of urban flooding is increasing due to the effects of increasing urbanisation and climate change. The use of storages is a relatively well-established approach to reduce peak flows and therefore reduce the need for costly upgrades to stormwater conveyance infrastructure. Recently, real-time control (RTC) has been considered as a means of increasing the performance of these storages. However, previous RTC studies have generally focussed on evaluating RTC with pre-determined storage layouts, i.e., storage locations and volumes, and have ignored the impact of optimising the storage layout. Hence, the objectives of this paper are (i) to introduce a two-step approach to minimising peak flows at the catchment scale by firstly optimising the layout of distributed storages and then optimising their RTC strategies, and (ii) to test the effectiveness of this approach on a real catchment in Adelaide, South Australia. Results show that distributed storage with optimised layouts can achieve significantly higher peak flow reductions than more commonly used end-of-system storage. These range from 5% for 100 m3 of system storage up to 40% for 700 m3 of system storage – whereas end-of-system storage achieved no peak flow reduction for up to 700 m3 of storage. The addition of optimised RTC to distributed storages is able to achieve an additional 10% in peak flow reduction. This increase in performance due to RTC is more significant for smaller system storage volumes. Analysis of the flood hydrographs shows the system peak flow reductions are achieved by attenuating hydrographs at individual storages, as well as delaying hydrographs to reduce their coincidence at the confluence of sub-catchments. These results highlight the potential for using optimised distributed storage layout and RTC as an alternative approach to end-of-system storage to reduce flood peaks.

Application of Hydrograph Analysis Techniques for Estimating Groundwater Contribution in the Sor and Gebba Streams of the Baro-Akobo River Basin, Southwestern Ethiopia

The Sor and Gebba watershed has undergone several natural and anthropogenic changes, as evidenced by the physical alterations and artificial mismanagement of water resources in the watershed. These situations alter the underground storage aquifer contribution to the streams. Thus, understanding baseflow of the watershed enables us to identify the groundwater system potential and dynamicity. The main objective of this research is to estimate baseflow using several hydrograph analysis techniques as there was neither an organized groundwater resources research carried out at the watershed level nor studies on various methods on estimation of baseflow contribution to these streams. Hence, this research involves estimating baseflow from daily streamflow data using the manual hydrograph analysis technique, Flow Duration Curve (FDC), timeplot, Web-based Hydrograph Analysis Tool (WHAT), the US Geological Survey Groundwater Toolbox (USGS GW Toolbox), and the Baseflow index program (BFI+). The analysis result shows that most automated filtering techniques used with presumed parameters have estimated above-average baseflow compared to the FDC and the manual hydrograph analysis techniques. Moreover, FDC and manual hydrograph analysis resulted in a below-average value of underground storage aquifer contribution to streamflow. The BFI values are proportional for the Sor and Gebba streams and estimated about 33% for the entire watershed.

Assessment of the low-water flow of the Ile river

The study examined the low-water flow of the Ili River in the Kapshagai Gorge. Data on low-water water consumption for the period 1940-2015 were collected. Hydrographs of the low-water flow for typical years are constructed. As a result of the analysis of hydrographs, the dates of the onset and end of the low-water periods of the Ile River were clarified. As a result of the analysis of hydrographs built on the hydrological post located 37 km below the HPP, the months October-November for the winter period and December-March for the winter period were taken. The characteristics of the low-water flow for the autumn and winter low-water periods are calculated. It was revealed that after the construction of the Kapshagai reservoir along the Ili River, there was a change in the low-water flow. Therefore, the hydrological calculations of the characteristics of the low-water water flow were carried out separately for the period 1940-1971, when the conditional natural water regime of the Ile River was still observed, and for the period from 1971 to 2015, when there was an increase in the anthropogenic load on the flow of the river basin. For these periods, the statistical parameters of the low-water flow of autumn and winter low water were calculated. It is shown that during the period of increased anthropogenic load on the Ili River, the coefficient of variation of the low-water flow series of the autumn low – water period increased more than twice, and for the winter period – significantly. The values of 75-97% of the low-water consumption security were determined for each period separately. It is shown that the low-water flow of the Ili River has significantly decreased over the last period.

A novel method for cold-region streamflow hydrograph separation using GRACE satellite observations

Abstract. Streamflow hydrograph analysis has long been used for separating streamflow into baseflow and surface runoff components, providing critical information for studies in hydrology, climate and water resources. Issues with established methods include the lack of physics and arbitrary choice of separation parameters, problems in identifying snowmelt runoff, and limitations on watershed size and hydrogeological conditions. In this study, a Gravity Recovery and Climate Experiment (GRACE)-based model was developed to address these weaknesses and improve hydrograph separation. The model is physically based and requires no arbitrary choice of parameters. The new model was compared with six hydrograph separation methods provided with the U.S. Geological Survey Groundwater Toolbox. The results demonstrated improved estimates by the new model particularly in filtering out the bias of snowmelt runoff in baseflow estimate. This new model is specifically suitable for applications over large watersheds which is complementary to the traditional methods that are limited by watershed size. The output from the model also includes estimates for watershed hydraulic conductivity and drainable water storage, which are useful parameters in evaluating aquifer properties, calibrating and validating hydrological and climate models, and assessing regional water resources.

Assessment of spring flows in Indian Himalayan micro-watersheds – A hydro-geological approach

Springs are an indispensable source of freshwater for mountain communities in the Indian Himalayan Region (IHR). Owing to the synergistic impact of anthropogenic and climatic factors, numerous perennial springs and streams in the region, are either becoming ephemeral or drying out, thus impacting the local people. Water scarcity, poverty, and limited scope of alternate livelihoods further reduce the communities’ resilience. Our focus is to assess the potential of reviving drying springs with the help of hydro-geological studies in water-scarce villages. The methodology involved high-resolution data monitoring of springs and first-order streams in two headwater micro-watersheds, namely, Shiv gadera and Haraita, in the rural Himalayas of Uttarakhand, India, with unalike topography and geology. To understand the hydro-geological processes and assess the flow regimes and aquifer storage dynamics, we applied water balance, correlation, flow duration, master recession curves analysis, and geological studies. The univariate and bivariate analysis shows that Shiv gadera has a better system memory, indicating a larger storage capacity than Haraita. The spring hydrograph responses also append that Shiv gadera has better storage and has a homogenous aquifer feed. The water balance, however, is in positive storage only during the rainy months in both the sites. The hydro-geological characterization from hydrograph analysis, recession analysis, and field surveys shows that Shiv gadera has intricate flow networks and slow flow velocities while Haraita is characteristic of transmissive fractured rocks. The spring flows in Shiv gadera are observed to be perennial and more groundwater contributes to spring discharges while Haraita exhibits intermittent to ephemeral nature. The recession curves also indicate uniform geology, a distinctive feed from recharge area, and slow emptying of the aquifer, while Haraita exhibits shallow storage and quick responses to storms. Spring flows in Shiv gadera show better stability than Haraita, as indicated by Q10/Q90 and Q50/Q90 measurements. These inferences qualify Shiv gadera as having a better chance of responding to management and treatments, thus a better potential for revival. The combination of hydrologic time series analysis and geological characterization used in this study could be a valuable approach for assessing spring revival in the IHR and has a potential for implementation across other parts of the Himalayas.

Impacts of Watershed Physical Properties and Land Use on Baseflow at Regional Scales

Study regionTexas, USA Study focusTexas is a large state in the US that experiences a diversity of climate conditions and water demands. In this study, 130 stream gauging sites and their associated watershed physical and geological properties were used to develop multiple regression models to predict the Baseflow Index (BFI) across Texas. Calculated BFI was derived from daily streamflow data from 1980 to 2017 using the two-parameter recursive digital filtering approach of the Web-based Hydrograph Analysis Tool (WHAT). Three scenarios were developed and validated. The first two scenarios related BFI to topography, climate, and land use. The third scenario used surface geology, soil type and hydrogeology parameters. New hydrological insights for the regionThe models developed showed high performance, low bias, and low relative errors to predict BFI, with R2 values varying from 0.72 to 0.99, and strong agreement with filtered BFI values. The results further showed that there was no specific pattern for BFI variation across Texas ranging from 0.29 to 0.51. Outputs indicated that models developed for scenarios 1 and 3 had higher prediction performance. Additionally, evapotranspiration (ET) contributed to lower model accuracy, since the ET was not categorized as proportional to the percentages of cultivated areas within each basin, but was generalized to represent the whole catchment. The developed models that are reported here can support further research in groundwater modeling and baseflow prediction for ungauged sites that have similar characteristics.

Determining the quasi monsoon front in the Indian Himalayas

Precipitation over the southern rim of the Indian Himalayan Region (IHR) mainly occurs due to two dominant synoptic weather systems: Indian winter (IWM: December, January, February) and summer monsoon (ISM: June, July, August, September). The genesis and evolution of these systems are extensively researched. Additionally, geographical location, season, orography controls the strengths of these systems along and across the southern rim of the IHR. However, plausible positioning of the frontal threshold limit of precipitation during IWM and ISM over the IHR remains an elusive scientific question. Thus, with the help of water samples collected in the upper Bhilangana River Basin (BRB in the central Himalayas), an attempt has been made to assess this frontal threshold limit of precipitation and is defined as “quasi monsoon front (QMF)" in the IHR. Results show depleted (enriched) stable water isotopic values at higher (lower) altitudes suggesting an elevation control. The intercepts of local meteoric water lines (LMWLs) of glacier ice/glacier melt (2.5), snow packs/snow melt (7.7), and stream water (10.3) reflect mixing of precipitation due to IWM and ISM. The d-excess values in water samples lie between the d-excess value of a typical IWM (~20‰) and ISM (~10‰), suggesting mixing of moisture from both Atlantic ocean – Mediterranean sea and Indian ocean-Bay of Bengal-Arabian sea. The tracer based hydrographic analysis indicates dominance of snow melt contributions to the regional hydrology. Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) model in the back trajectory mode estimates moisture sources of the IWM and ISM. Based on precipitation isotopic composition and associated moisture source regions, QMF oscillates in the northwest and southeast direction of the IHR depending on the strength and/or weakness of IWM and ISM. This work hypothesizes for upscale determination and description of the pulsatory extension of QMF in the central Himalayas (along BRB).

Physical modeling into outflow hydrographs and breach characteristics of homogeneous earthfill dams failure due to overtopping

The main objective of the present study is to introduce new empirical equations for the determination of breach geometrical dimensions and peak outflow discharge (Qp). Therefore, a historic failure database of 109 embankments was collected and examined. The most important factors that affect the breach evolution, including grading size, hydraulic, and outflow characteristics are also studied. Some of the parameters used for the determination of Qp and average breach width (Bave) have a significant effect on the erosion process, but they are less reflected in the technical literature. To study the behavior of non-cohesive soils during overtopping, 15 physical tests were performed at the laboratory, and the effects of interfering parameters were investigated. The experimental output hydrograph was used to simulate the hydrographs resulting from the failure of real dams, and recent artificial intelligence techniques along with linear and nonlinear regression models were employed. The area-time analysis of the laboratory hydrographs shows that the soil particle size and the characteristics of reservoir-basin significantly affect the rate of breach formation and outflow discharge. New relationships are introduced, based on the breach characteristics, by a combination of historical and experimental data, as well as case studies conducted on the hypothetical failure of 10 operational dams. The mathematical model is also used to simulate the process of breach evaluation. Based on statistical indices, comparison of the results, and sensitivity analysis, the developed equations can better express the susceptibility of materials to erosion and their application can minimize downstream vulnerabilities.

Biogeochemical Responses and Seasonal Dynamics of the Benthic Boundary Layer Microbial Communities during the El Niño 2015 in an Eastern Boundary Upwelling System

The Eastern South Pacific coastal zone is characterized by seasonal and interannual variability, driven by upwelling and El Niño Southern Oscillation (ENSO), respectively. These oceanographical conditions influence microbial communities and their contribution to nutrient and greenhouse gases recycling, especially in bottom waters due to oxygenation. This article addresses the seasonal hydrographic and biogeochemical conditions in the water and sediments during El Niño 2015. Bottom water active microbial communities, including nitrifiers, were studied using amplicon sequencing of 16S rRNA (cDNA) and RT-qPCR, respectively. The results of the hydrographic analysis showed changes in the water column associated with the predominance of sub-Antarctic Waters characterized by warmed and low nutrients in the surface and more oxygenated conditions at the bottom in comparison with El Niño 2014. The organic matter quantity and quality decreased during fall and winter. The bottom water active microbial assemblages were dominated by archaea (Ca. Poseidoniales) and putative ammonia oxidizing archaea. Active bacteria affiliated to SAR11, Marinimicrobia and Nitrospina, and oxygen deficient realms (Desulfobacterales, SUP05 clade and anammox) suffered variations, possibly associated with oxygen and redox conditions in the benthic boundary layer. Nitrifying functional groups contributed significantly more during late fall and winter which was consistent with higher bottom water oxygenation. Relationships between apparent oxygen utilization nitrate and nitrous oxide in the water support the contribution of nitrification to this greenhouse gas distribution in the water. In general, our study suggests that seasonal oceanographic variability during an El Niño year influences the microbial community and thus remineralization potential, which supports the need to carry out longer time series to identify the relevance of seasonality under ENSO in Eastern Boundary Upwelling Systems (EBUS) areas.

Estimation the hydraulic parameters of the fractured aquifer by using spring hydrograph analysis, Lange Bramke basin, Germany (Dept.C)

One characteristic of a fractured aquifer is the large contrast between the hydraulic parameters of fracture zone and that of the surrounding rock matrix. In this paper a trial to determine the aquifer constants of the Early Devonian sandstone fractured aquifer in Lange Bramke Basin, Germany was carried out applying Rorabaugh's conceptual model. This model was modified and used in estimating the hydraulic parameters of the conduit and diffuse flow systems from discharge hydrograph analysis. Daily discharge from a spring in the aquifer under consideration was continuously monitored for the period 12 June-31 Aug during 2001, 2002 and 2004. These records were used in recession hydrograph analysis. The identification different slopes in the recession hydrograph proceed to isolate each slope and to derive the ratio between transmissivity T and specific yield Sy (aquifer diffusivities T/Sy) from each slope. Two pumping and two slug tests were carried out during this study to check the estimated hydraulic parameters of the diffuse flow system. The results showed that the C.14 M. I. Gad T/Sy ratios derived from the recession hydrograph analysis ranged from 0.024 to 1.298 m2/sec with an average value of 0.438 m2/sec for conduit flow system, from 0.164 to 0.345 m2/sec with an average value of 0.222 m2/sec for intermediate-flow system and from 0.016 to 0.211 m/sec with average value of 0.107 m2/sec for diffuse flow system. Assuming Sy value for pure conduit equals 1.0, the resulted T value (0.438 m2/sec) was in order-of magnitude with T value obtained by tracer test (0.98 m2/sec). In addition, the T values for the rock matrix derived from analysis of the recession hydrograph ranged from 3.2x10-1 to 42,4 x10-4 m2/sec which is comparable with the range calculated from the aquifer tests (from 0.17x10-4 to 4.8x10-4 m2/sec). Since conduit systems typically display considerable spatial variability, it was concluded that the derived I values for the conduit flow system may need to be established at a local scale, while the values for the diffuse flow system may be applicable at a regional scale. As a result, the expensive isotope and/or tracer techniques in fractured rocks may be restricted to calibrate the more practicable and, according to the study, reliable analytical approaches for estimation the aquifer constants in fractured rocks.

The impact of climate change on flow conditions and wetland ecosystems in the Lower Biebrza River (Poland).

Water plays a key role in the functioning of wetlands and a shortage or contamination of it leads to changes in habitat conditions and degradation of ecosystems. This article scrutinizes the impact of climate change on the hydrological characteristics of floods (maximum flow, duration, volume) in the River Biebrza wetlands (North-East Poland). We analysed the trends in duration and volume of flood and maximum discharges in the historical period 1970–2000 and predicted these for the future periods 2020–2050 and 2070–2100, respectively. Next we assessed the impact on the wetland ecosystems. The basis of our assessments consists of statistical analyses of hydrographs and calculations by the Soil and Water Assessment Tool hydrological model and considering nine bias-corrected climate models. The results indicate that both volume and duration of winter floods will keep increasing continuously under Representative Concentration Pathways 4.5 and 8.5. The reduction in peak annual floods is expected to decline slightly in both scenarios. On the other hand, the analysis of trends in mean and standard deviation revealed negligible tendencies in the datasets for summer and winter hydrological seasons within the three time frames analysed (1970–2000; 2020–2050; 2070–2100). We foresee several future implications for the floodplain ecosystems. Shifts in transversal ecosystem zonation parallel to the river will likely take place with more highly productive flood tolerant vegetation types. Nutrient availability and algal blooms during spring inundations will likely increase. Slowdown of organic matter turnover later in summer will lead to a higher peat accumulation rate. Logistical problems with summer mowing and removal of bushes in winter may enhance shrub encroachment.

Evidence of Hydrological Intensification and Regime Change From Northern Alaskan Watershed Runoff

AbstractSnowmelt‐dominated runoff regimes have defined northern Alaskan rivers. Discharge records from three watersheds within the National Petroleum Reserve in Alaska (NPR‐A) span 19 years and capture three notable periods of changing runoff. In the first, 2001–2008, mean annual runoff (MAR) averaged 90 mm, characterized by sharp snowmelt runoff and summer drought. Over the next 7 years, larger MAR averaged 120 mm driven by high and early snowmelt runoff. The most recent 4 years, 2016–2019, had even higher MAR of 163 mm with high and sustained late summer flows. Hydrograph analysis suggests a shift toward rainfall‐dominated runoff in the most recent period compared to snowmelt‐dominated hydrographs in the previous two. Declining sea ice appears closely linked to increasing late summer precipitation and a shift toward rainfall runoff. Future development in the NPR‐A will require continued hydrological monitoring and planning to mitigate flood and erosion hazards, permafrost degradation, and ecosystem impairment.

WebGIS development for base flow separation and recharge estimation

The basic flow rate is characterized by an important hydrological component being responsible for the estimation of the water recharge. Due to the difficulty of measurement, mathematical methods are used to calculate the flow separation. However, when hydrographic analysis is based on long historical series, the use of these methods becomes impracticable, making it necessary to use computational resources. A WebGIS (Web Geographical Information System) was developed for data selection and calculation of base flow separation, based on hydrological data from fluviometric stations located in the Taquari-Antas basin, located in the state of Rio Grande do Sul. A modified version of the Unified Process was used as a software development methodology. We used the MVC software architecture standard and the programming languages PHP 7.0, HTML5, JS and CSS3 for programmatic development of the constituent layers of the system. The hydrological data comes from the HIDROWEB portal, part of the National Information System on Water Resources (SNIRH), with hydrological information collected by the National Hydrometeorological Network (RHN) coordinated by the National Water Agency (ANA). The system facilitates the use of remote and distributed hydrological data, shared over the Internet, for various hydrological analyzes.

Regional patterns in hydrologic response, a new three-component metric for hydrograph analysis and implications for ecohydrology, Northwest Volcanic Aquifer Study Area, USA

Study RegionOregon, California, Idaho, Nevada and Utah Study FocusSpatial patterns of hydrologic response were examined for the Northwest Volcanic Aquifer Study Area (NVASA). The utility of established hydrograph-separation methods for assessing hydrologic response in permeable volcanic terranes was assessed and a new three-component metric for hydrograph analysis was developed. The new metric, which partitions streamflow into subcomponents defined by the timescales of hydrologic response (e.g., fast-runoff, intermediate-interflow and slow-baseflow), was used to gain a fundamental understanding of the regional hydrology, investigate sub-regional differences, influencing factors, and ecohydrological implications. New Hydrological InsightsThe combined effects of NVASA’s physiography, climate and geology create a strongly coupled surface-groundwater system that produces copious baseflow and limited quantities of runoff and interflow. Patterns of hydrologic response are influenced by the type and rate of precipitation and permeability of the underlying geology. Under variable precipitation conditions the hydrologic response of volcanic terranes with similar permeability and subsurface-storage capacity can be significantly different. From a water management and ecohydrology perspective, understanding regional patterns of hydrologic response and sub-regional differences is fundamental. Results indicate that minimum-flow methods provide the most conservative estimate of baseflow and may be the most robust for filtering out snowmelt bias in baseflow estimates. Baseflow contributes ∼75% of the perennial streamflow across the NVASA and represents a critical component of the regional water supply that provides critical cold-water habitat.

Quantifying Coastal Fluvial Morphodynamics Over the Last 100 Years on the Lower Rio Grande, USA and Mexico

AbstractDownstream changes in fluvial channel morphology are commonly observed in association with the backwater zone, where rivers transition from quasi‐uniform flow with normal‐flow depth to gradually varying flow. This transition is linked to changes in channel morphology and mobility and resulting fluvial stratigraphy. However, the majority of systems studied to date are perennial rivers with relatively consistent flow conditions. Here we investigate the evolution of a large river with significant flood‐to‐baseflow variability as it transverses and builds a large delta. We provide the first comprehensive study of the morphology and morphodynamics of the lower Rio Grande, a major continental drainage system that enters the western Gulf of Mexico. We quantify the morphology of the current Rio Grande channel and document spatial trends in channel geometry and kinematics using lidar, historical surveys, and hydrographic analysis. The modern Rio Grande channel morphology does not significantly vary toward the coast. Rather, the channel width, levee, and bed slopes remain nearly constant for ~200 river km. We find historical migration rates between 10 and 100 m/yr with no significant reduction toward the coast in contrast to previously studied systems. We propose that this invariant channel geometry and sustained high migration rates are signatures of the channel not requiring adjustment within the lower coastal reach to accommodate baseflow conditions, and the channel remains continuously adjusted solely to peak flow conditions.

Retention Pond and Pump Station as an Alternative To Flood Management In Bengawan Jero Irrigation Area

Water is the source of life to all living organisms. But in a very large volume, water can be problematic to life. One of problems generated by a large volume of water is flood disaster. River, as a water source, is one of natural resources with multifunction to human beings. Some areas in Indonesia have increasing flood intensity as the rainy season comes. Retention pond and pump station is one solution to dealing with flood puddle occurring in area. One of areas experiencing flood routinely annually is Bengawan Jero Irrigation Area (D.I. Bengawan Jero). The design of retention pond and pump station in DI Bengawan Jero was calculated using flood flow rate with repeated period of 10 years. From the result of rainfall data processing with repeated period of 10 years using Nakayasu method, it could be found Qplanngci of 7.37 m3/s at hour 1. The storage volume needed to deal with flood in the Retention Pond in Bengawan Jero Irrigation area is 3.909 m3, using 2 pumps with capacity of 2.5 m3/s. From hydrograph analysis, it could be concluded that the use of retention pond and pump station can control the peak flow rate by suppressing or cutting the flood peak to occur.

Groundwater connectivity of a sheared gneiss aquifer in the Cauvery River basin, India

Connectivity of groundwater flow within crystalline-rock aquifers controls the sustainability of abstraction and baseflow to rivers, yet is often poorly constrained at a catchment scale. Here groundwater connectivity in a sheared gneiss aquifer is investigated by studying the intensively abstracted Berambadi catchment (84 km2) in the Cauvery River Basin, southern India, with geological characterisation, aquifer properties testing, hydrograph analysis, hydrochemical tracers and a numerical groundwater flow model. The study indicates a well-connected system, both laterally and vertically, that has evolved with high abstraction from a laterally to a vertically dominated flow system. Likely as a result of shearing, a high degree of lateral connectivity remains at low groundwater levels. Because of their low storage and logarithmic reduction in hydraulic conductivity with depth, crystalline-rock aquifers in environments such as this, with high abstraction and variable seasonal recharge, constitute a highly variable water resource, meaning farmers must adapt to varying water availability. Importantly, this study indicates that abstraction is reducing baseflow to the river, which, if also occurring in other similar catchments, will have implications downstream in the Cauvery River Basin.

Application of Sustainable Road Drainage System: Simulation by Using SWMM Program

High levels of rainfall are generally followed by increased volume of surface runoff and the potential for standing water. Stagnant water on the roads has a negative impact on road users and road damage. The concept of sustainable road drainage has the potential to be developed in dealing with the quantity of runoff water. This study aims to evaluate the existing road drainage system and implement a sustainable road drainage system. The location chosen as the object of research is Diponegoro University Campus area, Tembalang District, Semarang City. Use of the SWMM program which contains a set of flexible hydraulic modeling capabilities used to direct runoff and external inflows through a network of pipe drainage systems, channels, storage units and diversion structures.From the results of the hydrograph analysis, the largest discharge was found in the Outfall of the Center for Environmental Research with a discharge of 5.7 m3 / sec and the lowest discharge at the outfall of the Faculty of Business Economics with a discharge of 0.07 m3 / sec. Whereas the longest flood time that occurred was at the Outfall of the Faculty of Business Economics with a time of 4 hours 45 minutes and the shortest flooding time was at the Jurang Belimbing Outfall with 1 hour and 15 minutes. The sustainable road drainage system model applied is a road drainage channel with the addition of fine and coarse aggregate filters to the channel and integrated with infiltration wells. Thus, the drainage channel is able to reduce surface water flow to other areas and improve water quality.