Surface Runoff Research Articles

The increasing water stress projected for China could shift the agriculture and manufacturing industry geographically

The sustainable development of China has been challenged by the misalignment of water demand and supply across regions under varying climate change scenarios. Here we develop a water stress prediction index using a fuzzy decision-making approach, which analyzes spatiotemporal variations of water stress and concomitant effects on the populace within China. Our results indicate that water stress will increase from 2020 to 2099 under both low and high emission scenarios, primarily due to decreased water supplies like surface runoff and snow water content. Seasonal analysis reveals that annual fluctuations in water stress are mainly driven by changes in spring and autumn. Water stress is projected to be considerably lower in southeastern provinces compared to northwestern ones, where, on average, over 20% of the Chinese population could be severely impacted. These changes in water stress could lead to the north-to-south migration of the agriculture sector, manufacturing sector, and human population.

Cover Crop Effects on Surface Runoff and Subsurface Flow in Rainfed Hillslope Farming and Connections to Water Quality

Abstract: Surface runoff and subsurface flow patterns were monitored in hillside runoff plots in almond and olive orchards with soils covered with spontaneous plants over two hydrological years. The experimental runoff plots were located on the south flank of the Sierra Nevada (Lanjarón, SE Spain) at 580 m a.s.l. with an area of 40 m2 (10 m × 4 m). The surface and subsurface discharge were collected and measured at different soil depths (0, 5, 10, 25, and 50 cm), and the dissolved nutrient concentrations (NO3–N, NH4–N, PO4–P, and K) were determined. According to the findings, the subsurface flow pathways drained most of the rainfall water compared with surface runoff, which was affected by plant cover. The influence of rainfall intensity (I30) on surface runoff was more meaningful than that on subsurface flow. Throughout the monitoring period, the runoff coefficients at soil depths of 0, 5, 10, 25, and 50 cm averaged 0.04, 0.11, 0.14, 0.17, and 0.18, respectively. Subsurface flow was one of the dominant pathways for N and K loss, whereas P loss mainly occurred via surface runoff. Moreover, the concentrations in subsurface flow were higher than the recommended level for standard water quality for NO3–N, NH4–N, and PO4–P. Subsurface flow was the main route of dissolved nutrient delivery, making these nutrients available to the root systems of trees, where nutrient uptake is more likely to occur. Thus, by lessening surface runoff and encouraging surface vegetation coverage to facilitate the recycling of nutrients and buffer the rainfall’s impact on the soil surface, nutrient loss control can be achieved.

Shallow groundwater and river baseflow: Interconnection evidences and integrated water management strategies. Case study in the upper Descoberto watershed, Federal District, Brazil

Aquifer discharge in the form of baseflow is intimate related to river replenishment. In this manner, it is reasonable that water management practices consider an integrated approach including surface and groundwater. Effective regulatory measures, however, require the understanding of the mechanisms and the degree of such interconnection. In the Federal District, capital of Brazil, research focused on this theme are scarce, despite the relevance addressed by some authors. In the present study, shallow groundwater of Upper Descoberto Watershed was monitored for four years (2019–2023). The area responds to 60% of local population public water supply and has been facing land use conflicts and water crisis. Data were collected with 2-h resolution and compared to fluviometric stations discharge and water height records. Graphical analyses demonstrate that river baseflow is highly dependent on shallow aquifer discharge. The decrease of the phreatic aquifer water level results, in a short period, in streams flow reduction. This result is contrasting to the former agreement that considered the connection would take more time to be established. Statistical correlation coefficients are as high as 0.920 for the entire monitoring range and 0.998 for the dry season. The results evidence that soils have important reservoir and regulatory functions, even though they might not be relevant for high water demand activities. In this way, water grant process should account for correlated components, such as territory planning, estimation of total extraction by sensitive areas and properly characterization of insignificant uses, alternative and independent water sources evaluation, and definition of environmental constraints. The mitigation practices of hydric problems must include the implementation of artificial recharge devices, use of sustainable farming methods and control of rainwater overland flow. It is desirable the maintenance and enlargement of the current monitoring net so that former patterns that culminated in water crisis can be early identified and mitigated.

The analysis of potentially toxic heavy metal contamination in the Lake Bogoria geothermal springs

Lake Bogoria geothermal system is a natural geological site in Kenya that boasts a habitat for Flamingos which attract tourists, and its water find applications in agriculture and recreation. Accordingly, its geological processes, closed water systems and anthropogenic activities may lead to accumulation of potential toxic metal contamination. The present study focused on the analysis of potentially toxic metals — manganese (Mn), cadmium (Cd), lead (Pb), copper (Cu) and nickel (Ni) using atomic absorption spectrometry (AAS) in geothermal spring water samples after acid digestion method, and evaluated their health risks through dermal and ingestion exposures. Principal component analysis (PCA), enrichment factors (EF) and Pearson correlation coefficient (PCC) were performed to determine the sources and correlation between the metals investigated. Manganese, Cu and Ni recorded mean concentrations (ppm) of 0.19 ± 0.08, 0.02 ± 0.02 and 0.03 ± 0.02, respectively, which were below the permissible World Health Organisation (WHO) limits, whereas Pb (0.06 ± 0.04) and Cd (0.05 ± 0.02) levels were above the threshold standards. PCA revealed that these metals may have originated from geological regimes and surface run-offs. Copper and Cd metals were highly enriched indicating an anthropogenic origin. The Hazard quotients (HQ) of Pb and Cd were >1,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$>1,$$\\end{document} hence they are potential precursors for non-carcinogenic and carcinogenic risks in both children and adults. The findings of this study showed possible Pb and Cd metal contamination from geothermal waters. Therefore, there is need for remediation, continuous monitoring and assessment of geothermal waters before utilization for recreation, crop production and geothermal energy exploitation to ensure environmental conservation and human safety.

Investigation of the Basin Characteristics through Morphometric Analysis of Hadejia River Sub-Basin: Implications for Groundwater Recharge

Understanding the geohydrological properties of a drainage basin in relation to the topographical feature and its flow patterns depends heavily on morphometric analysis. Estimating a watershed's frequency of infiltration and runoff as well as its other hydrological characteristics is also helpful. The study was conducted using Geographical Information System (GIS) techniques with the aim of establishing relationship between surface morphometry, underlying geology and groundwater recharge. For detailed measurement and analysis, Digital Elevation Model (DEM) and high resolution imageries were employed for basin delineation, slope characterization, channel network extraction and stream ordering in order to derive the linear, areal, and relief aspects of morphometric parameters. The findings showed that a total number of 116 streams joined the 4th order stream in which 83 streams were 1st order, 25 streams were 2nd order, 7 streams were 3rd order and the major trunk was 4th order stream, occupied an area of 1486.86km2. The stream network's drainage system exhibits dendritic design. The results further indicate that the values for stream frequency, infiltration number, drainage density, drainage texture, length of overland flow, elongation ratio and basin relief are 0.08, 0.032, 0.41km/km2, 0.023, 1.22km, 0.54 and 28.59m respectively. The observed values of both linear, areal and relief parameters were generally low. Low values for the areal and relief criteria indicates that the sub-basin is at its youthful stage of development and possesses very good permeable subsurface formation and prospect with the possibility of high potential groundwater resources. The result help us understand the connections between hydrological variables and geomorphological parameters as guidance and/or decision-making instruments for the authorities to develop decisions for the environmentally friendly growth of the basin, water supply planning, water budgeting, and disaster mitigation within the Hadejia river sub-basin.

Protozoan communities serve as a strong indicator of water quality in the Nile River

The relationship between the protozoan communities and environmental variables was studied in the Nile River to evaluate their potential as water quality indicators. Protozoans were sampled monthly at six sampling sites in the Nile's Damietta Branch across a spatial gradient of environmental conditions during a 1-year cycle (February 2016–January 2017). The Protozoa community was comprised of 54 species belonging to six main heterotrophic Protozoa phyla. The abundance (average, 1089 ± 576.18 individuals L−1) and biomass (average, 86.60 ± 106.13 μg L−1) were comparable between sites. Ciliates comprised the majority of protozoan species richness (30 species), abundance (79.72%), and biomass (82.90%). Cluster analysis resulted in the distribution of protozoan species into three groups, with the most dominant species being the omnivorous ciliate Paradileptus elephantinus. Aluminium, fluoride, and turbidity negatively affected abundance and biomass, while dissolved oxygen and potassium positively impacted biomass. Of the dominant species recorded over the study area, the amoebozoa Centropyxis aculeata was associated with runoff variables, while the bacterivorous ciliates Colpidium colpoda, Glaucoma scintillans, and Vorticella convallaria were related to the abundance of heterotrophic bacteria, phytoplankton biomass, and total organic carbon. Total dissolved salts, PO4, NH3, NO2, dissolved oxygen, and total organic carbon were the strongest causative factors for protozoa distribution. The α-Mesosaprobic environment at site VI confirmed a high load of agricultural runoffs compared to other sites. This study demonstrates that protozoans can be a potential bioindicator of water quality status in this subtropical freshwater river system.

Modeling Reliability Analysis for the Branch-Based Irrigation Water Demands Due to Uncertainties in the Measured Surface Runoff

This study aims to model the uncertainty and reliability quantification of estimating the planning irrigation water demands in the multi-canal irrigation zone, named the RA_IWD_Canal model. The proposed RA_IWD_Canal could estimate the zone-based and branch-based water demands and quantify their uncertainties and reliabilities via the weighted frequency quantile curves. The historical planning irrigation water demands and measured surface runoff from 2019 to 2024 in the Zhudong irrigation zone are utilized in the model development and application. Using the proposed RA_IWD_Canal model, the estimated branch-based irrigation water demands exhibit a significant variation (on average, from 0.02 m3/s to 1.7 m3/s) in time and space attributed to uncertainties in the historical gauged surface runoff. Also, the Zhudong Canal zone is demonstrated to be sufficiently supplied irrigation water subject to existing introduced water demands with a high reliability of 0.85; instead, the associated branches have considerable difficulty achieving the expected irrigation efficiency based on the desired water requirements with low reliability (nearly 0.25). To keep all branches in the irrigation zone consistent in irrigation efficiency, the probabilistic-based water demands could be introduced via the proposed RA_IWD_Canal model with the desired reliability.

Perancangan Sistem Penyaliran Tambang Pada PIT XYZ PT Karya Bhumi Lestari Jobsite PT Kartika Selabumi Mining Desa Kedang Ipil Kota Bangun II Kabupaten Kutai Kartanegara Provinsi Kalimantan Timur

Water is one of the things that is very influential in the mining process, mining water is water that is at the location and/or comes from the process of mining activities, both mining and processing, including runoff water in the mining area. Surface runoff water is rainwater that overflows into mining areas and is not a result of mining activities. The open pit mining method will cause the formation of a large basin so that it has the potential to become a water storage area, both from surface runoff and groundwater. During extreme weather conditions with high rainfall, water from surface runoff can inundate the ground floor and cause the mining front to become muddy, which can hamper mining activities. Handling waterlogging in mining forts requires good pumping performance, as well as re-planning the mine drainage system for the mine progress area. So that mining activities run smoothly and the mining front is free from puddles of water after rain, the drainage system must be well designed. Based on research that has been carried out, the total area of ​​the Catchment Area is 52.14 Ha with a runoff discharge of 82,567.79 m³/month. The planned discharge using the MF-290 Pump with RPM 1600 is, 290.00 m³/hour or 123,540.00 m³/month. After comparing the MF-290, MF-385 and DND-200 pumps, the MF-290 pump was selected for use. This is because the fuel consumption of the MF-290 is smaller so it saves costs and it is also deemed sufficient to use the MF-290 pump. Pump Ratio on the MF-290 pump April 6.71. May 3.93, June 6.44, July 6.36 and August 8.83, which means the pump is safe to use because the ratio is >1.

The role of near‐surface vegetation in modulating overland flow resistance in grasslands of the Chinese Loess Plateau

AbstractVegetation restoration significantly increases overland flow resistance and decreases soil erosion. The cause of soil erosion is unknown, though grain resistance and form resistance are frequently confused with the overall overland flow resistance. The zonal specie of Bothriochloa ischcemum (Linn.). Keng (BI) and the dominant specie of Artemisia vestita Wall. ex Bess (AG) were selected to investigate the effect of vegetation near soil surface characteristics derived by vegetation restoration on overland flow resistance of grain resistance and form resistance. In total, 24 steel tanks were planted at six planting densities of 5, 10, 15, 20, 25, and 30 plants m−2, and two tanks were used as bare soil controls. Their hydraulic characteristics were tested under a constant rainfall intensity (60 mm h−1) on a 26.2% slope. The results showed that the grain resistance (fg) and form resistance (ff) ranged from 0.06 to 0.35 and 18.01 to 95.77 under six planting densities. Vegetation increased overland flow resistance by more than 90%, which was mainly attributed to ff. Vegetation near soil surface factors of the aboveground part, biological soil crusts, and root collar increased ff by 18.71 to 82.13, 0.74 to 11.50, and 1.61 to 3.40, respectively. Compared with BI, the mean value of fg in AG was 48.87% lower, whereas the mean value of ff was 1.36 times greater. The fg decreased with soil organic matter as a power function. The ff decreased with the Reynolds number, Froude number, and flow velocity and increased with vegetation coverage, aboveground biomass, and root collar area as power functions. Soil properties explained the majority of the variation in fg, and near the vegetation soil surface factors explained the majority of the variation in ff. Finally, ff was simulated using the Reynolds number, vegetation coverage, and root collar area. In addition, a simulation equation for the total flow resistance was established by distinguishing the grain resistance and the form resistance, and the performance of the model developed in this study was satisfactory (NSE = 0.97).

Impact of a WWTP effluent overland flow on the properties of a mediterranean riparian soil

In this work we aim to assess the impact of a WWTP effluent overland flow on properties and nutrient concentrations of a riparian soil, in order to explore the potential of this practice as a nature-based treatment. We set two study zones of 150 m2 on the field, one control and one that received the WWTP effluent on its surface for one month. Samples were taken before and after the effluent overland flow system, to test the impact of the effluent on soil properties through a BACI design, and after 17 months, to evaluate the recovery of the soil. Two depths were studied: 0–5 cm and 5–20 cm. The effluent overland flow triggered an increase in exchangeable sodium percentage and a decrease in nitrate concentration in both depths, and an increase in ammonium concentration in 0–5 cm depth. After 17 months, there were not found relevant differences among zones. In conclusion, this practice could be used in the purpose to reduce the nutrient concentrations of WWTP effluents. This practice could be relevant for regions where WWTP effluents are discharged in low-flow or intermittent streams, such as semi-arid regions or the Mediterranean region.

Acute Toxicity of Malathion, Permethrin, and Roundup on the Tropical Freshwater Shrimp Xiphocaris elongata (Guérin-Méneville, 1855)

Urban and agricultural runoffs can transport contaminants and pesticides into freshwater ecosystems, particularly in the developing tropics. For instance, organophosphate and pyrethroids pesticides, such as Roundup, Malathion, and Permethrin, have been found in tropical streams. The uncontrolled application of these pesticides has become a growing concern due to their adverse effects on various non-targeted organisms. Unfortunately, most studies have focused on a few selected model species, ignoring the effects on other non-target organisms, which may play an important role in tropical lotic ecosystems. In addition, the biological characteristics of aquatic crustaceans, including their morphology, physiology, and behavior, make them susceptible to toxic chemicals. For this reason, this study used the widely distributed freshwater shrimp Xiphocaris elongata as a model organism to determine the acute toxicity of Permethrin, Malathion, and Roundup. Our results show that the proportion of mortality of X. elongata in each concentration group became progressively higher as the concentration of exposure increased. We also found that the synthetic pyrethroid Permethrin was the most toxic pesticide tested, with a median lethal concentration (LC50) value for 96 h of 3.96 × 10−6 µg·L−1, followed by organophosphate Malathion (8.87 µg·L−1) and Roundup (748.92 µg·L−1). Experiments with this freshwater shrimp showed a good control performance and reproducibility for the tested pesticides. This study demonstrated that X. elongata is a suitable test organism that can be a representative bioindicator of pesticide toxicity in tropical streams.

Mercury sources, transport, and transformation in rainfall-runoff processes: Mercury isotope approach

Mercury (Hg) in runoff water poses significant ecological risks to aquatic ecosystems that can affect organisms. However, accurately identifying the sources and transformation processes of Hg in runoff water is challenging due to complex natural conditions. This study provides a comprehensive investigation of Hg dynamics in water from rainfall to runoff. The Hg isotope fractionation in water was characterized, which allows accurate quantification of Hg sources, transport, and transformations in rainfall-runoff processes. Δ200Hg and corrected Δ199Hg values can serve as reliable tracers for identifying Hg sources in the runoff water and the variation of δ202Hg can be explained by Hg transformation processes. During runoff migration processes, Hg from rainfall is rapidly absorbed on the land surface, while terrestrial Hg entering the water by the dissolution process becomes the primary component of dissolved mercury (DHg). Besides the dissolution and adsorption, microbial Hg(II) reduction and demethylation of MeHg were dominant processes for DHg in the runoff water that flows through the rice paddies, while photochemical Hg(II) reduction was the dominant process for DHg in the runoff water with low water exchange rates. Particulate Hg (PHg) in runoff water is dominantly originated by the terrestrial material and derived from the dissolution and adsorption process. Tracking sources and transformations of Hg in runoff water during the rainfall-runoff process provides a basis for studying Hg pollution in larger water bodies under complex environmental factors.

Moisture patterns and fluxes in evolving tafoni developed in arkosic sandstone in temperate climate

AbstractCavernous weathering forms have long been studied and discussed as enigmas in geomorphology. Recently, their evolution has been shown to be controlled by moisture patterns, which are still poorly understood. For the first time, capillary water and vapor fluxes were characterized in detail at tafone in a temperate climate of central Europe using a wide range of methods adapted from soil hydrology. Time domain reflectometry showed that moisture flows from the rock interior to the evaporation front in the shallow subsurface of both — the backwalls and the outer surface. When overland flow occurs on the outer surfaces (after heavy rains), 10 mm/day can infiltrate and flow toward the backwalls. The main sources of water for tafone are the influx of water from the rock interior and the infiltration of overland flow after heavy rains, while condensation of air humidity is a minor source. Influx from the rock interior is coupled to the evaporation rate, which varies between 100 and 300 kg/m2/year in summer and less than 15 kg/m2/year in winter. More water evaporates from the backwall of the tafone than from the outer surface, and more salt is deposited in the backwalls, resulting in predominant salt weathering in the backwalls. The tafoni studied thus evolve, and the cavities deepen. Tafoni in arid and semi‐arid environments generally show a much higher contrast between evaporation rates from backwalls and outer surfaces than tafoni and honeycombs in temperate and coastal environments. Tafoni in temperate settings are therefore more susceptible to degradation when evaporation decreases or inflow to the tafone increases. This study also shows that microtensiometers can be used to determine moisture content with high spatial resolution, while time domain reflectometry allows accurate characterization of moisture patterns with depth.

Computationally efficient Watershed-Scale hydrological Modeling: Integrating HYDRUS-1D and KINEROS2 for coupled Surface-Subsurface analysis

Watershed flow processes consist of partitioning, movement, storage, and redistribution of water fluxes in space and time. However, the integrated modeling of these processes is challenging due to computational burden, extensive data requirements, and/or reliance on simplifying assumptions. This study introduces a novel and computationally efficient modeling framework that leverages two state-of-the-art process-based models: HYDRUS-1D (H1D) for unsaturated flow and KINEROS2 (K2) for overland flow. The framework extends a hillslope-scale coupled H1D-K2 model to simulate watershed-scale processes, where H1D replaces the three-parameter Parlange’s infiltration equation in the event-based K2 model. Boundary condition switching is employed to account for surface ponding and water exchange between the two model domains. The structure of the coupled watershed-scale H1D-K2 model consists of a cascade of connected rectangular planes, channel elements, and 1D soil profiles to simulate 1D overland flow, infiltration, unsaturated zone flow, and recharge. Computational efficiency relative to HYDRUS-2D is achieved through a dynamic time-stepping approach and dimensionality reduction. The watershed scale model improved the computational time by 14.3% and 47% compared to the corresponding Hillslope scale H1D-K2 and HYDRUS-2D, respectively. The performance and efficiency of the new watershed model are demonstrated using benchmark watershed and/or hillslope simulations. Calibrated hydrographs and water balance components using Walnut Gulch Experimental Watershed data, showed excellent agreement with observed data with a Nash-Sutcliffe coefficient (NSC) greator than 0.8 and Pearson correlation coefficient (R2) greater than 0.92.

Water chemical formation mechanism and water quality analysis of Shichuan River under the influence of human activities

ABSTRACT It is necessary to analyze the characteristics of the water environment and factors influencing the basin in order to determine its current ecological status. This study aims to investigate the chemical properties in the Shichuan River Basin using Gibbs diagram, Piper triangle diagram, correlation analysis, factor analysis, and main ion ratio method. The enhanced Nemerow comprehensive index method and fuzzy comprehensive evaluation method are employed for river water quality assessment. The findings reveal that runoff water has a weak alkaline nature with low salinity. The hydrochemical type of river water includes Ca2++Mg2++Na+-SO4 2-, Ca2++Mg2+-SO4 2-+Cl-+HCO3 -, Ca2++Na+-SO4 2-+Cl-+HCO3 -. Silicite and dolomite weathering are identified as primary influencing factors, while evaporite weathering also contributes to variations in chemical composition within the basin's waters. Ca2+, Mg2+, SO4 2- and HCO3 - originate from carbonate rock and silicate rock weathering processes, whereas Na+, K+ and Cl-, are primarily derived from evaporite weathering influenced by domestic sewage and agricultural activities. Agricultural production practices along with discharge of domestic sewage have an impact on Na+, K+, Cl- and NO3 -concentrations in aquatic systems. Water quality at all three monitoring sections falls under level IV classification. Phosphorus emerges as a key limiting factor for eutrophication within this basin's watersheds.

Model linkage to assess forest disturbance impacts on water quality: A wildfire case study using LANDIS(II)-VELMA

Wildfires in western US forests increased over the last two decades, resulting in elevated solid and nutrient loadings to streams, and occasionally threatening drinking water supplies. We demonstrated that a linked LANDIS (LANDscape DIsturbance and Succession)-VELMA (Visualizing Ecosystem Land Management Assessments) modeling approach can simulate wildland fire effects on water quality using the 2002 Colorado Hayman Fire. Utilizing LANDIS-II's forest landscape model to simulate forest composition and VELMA's eco-hydrologic model to simulate pre- and post-fire water quantity and quality, the best calibration performance yielded a Nash-Sutcliffe Efficiency (NSE) of 0.621 during 2000–2006 (most optimal annual - 0.921) in comparison to North American Land Data Assimilation System (NLDAS) runoff. Pre-fire modeled runoff, nitrate, and surface water temperature (SWT) correlated with observations. Simulated post-fire runoff (229%) and SWT (20.6%) were elevated relative to pre-fire, with nitrate concentrations 34 times greater than the aquatic life threshold (0.01 mg N/L).

UIDS: A Matlab-based urban flood model considering rainfall-induced and surcharge-induced inundations

The Urban Inundation-Drainage Simulator (UIDS) is a new coupled model for simulating urban flooding dynamics, developed as an open-source, MATLAB-based platform. It integrates a rainfall-runoff model with a two-dimensional overland flow model (OFM) and a one-dimensional sewer flow model (SFM). Unlike conventional models limited to either rainfall-induced or sewer surcharge-induced flooding, UIDS captures bidirectional surface-underground interactions to simulate both processes simultaneously. The OFM employs an explicit time-stepping scheme and robust wet-dry front treatment, while a weir equation describes roof-to-ground flow exchange for numerical stability. Timing synchronization facilitates continuous OFM-SFM coupling. Benchmarking and case studies of Gangnam flood events demonstrate UIDS's ability to accurately simulate urban flooding, particularly subcritical flows. The open-source nature of UIDS allows user flexibility in accessing and modifying the MATLAB code. Ultimately, UIDS is expected to serve as an accessible and adaptable tool for urban flood modeling and risk assessment.

Selecting the Effective Biochar for Removal of Pollutants from Highway Stormwater Runoff

Selecting the Effective Biochar for Removal of Pollutants from Highway Stormwater Runoff

Morphometric Analysis of Mithmumbri - Malvan Area, Sindhudurg District, West Coast of Maharashtra, India

Morphometric analysis has been carried out from the Mithmumbari to Malvan area, Western part of Maharashtra in Sindhudurg district, India. The morphometric analysis is carried out in fourteen drainage basins, viz., Achra, Pyali, Golvan, Mithmumbari, Katvan, Kamtakhudi, Gavaliwadi, Kunkeshwar, Kandalgaon, Munge, Malvan, Masura, Belachiwadi and Tambalwadi. The morphology of these basins is governed by a number of drivers including tectonic processes mainly the Vijaydurg fault, Mithbav fault, Malvan fault and lineaments, climate and lithology that influence the river system over a range of timescales. The majority of the basins are highly dissected and structurally controlled. The drainage density is low, with moderate to steep slopes within the elongated basin. The Achra, Pyali, Golvan, Gavaliwadi, Kandalgaon, Munge and Malvan basins are structurally controlled. The lower values of length of overland flow in study area reveal that stream erosion is more dominant than sheet erosion. Achra, Pyali, Mithmumbri, Golvan and Malvan basins are higher stream power, which represents higher erosion of the basin indicates high river basin management measures. Achra, Pyali, Golvan, Katvan, Kamthakhudi, Gavaliwadi, Kunkeshwar, Munge, Masura, Belachiwadi and Tambalwadi basins are rapid uplift stage of the basin. The Achra, Pyali, Golvan and Kamthakhudi basins can be inferred as SSW tilting in response to tectonic tilt. The hypsometric analysis shows eight basins (Achra, Pyali, Mithmumbari, Kamtakhudi, Kunkeshwar, Gavaliwadi, Belachiwadi and Tambalwadi) under the mature stage, five basins (Katvan, Munge, Kandalgaon, Malvan and Masura)in the youth stage and one basin (Golvan) under the old stage. The mature stage drainage basins show significant incision and entrenchment as a result of the Late Quaternary upliftment of the study area. The stages of drainage basins development in the western part of Maharashtra thus identify tectonically active and quiescent phases. Keywords: Morphometric and Hypsometric Analysis, Structural Control Basin, RS-GIS, Sindhudurg District, West Coast of Maharashtra

A historical overview of experimental hydrology in China

AbstractThe history of experimental hydrology in China is important but poorly documented. Here we review 94 papers (86 of these in Chinese) from the CNKI and Web of Science websites to chronicle the history of experimental studies in China before 2000. Professor Wei‐Zu Gu—the focus of this Special Issue—factors heavily into this history. Perhaps more than any country, the experimental hydrology history of China is influenced by socioeconomic development and political change. Our analysis shows 4 main periods of development associated with (1) an early development stage before 1949, the founding year of People's Republic of China (PRC), (2) an initial period of rapid transition in experimental studies in China (1949–1965), (3) a struggling and recovering stage for during and shortly after the Cultural Revolution, from 1965 to 1978, and (4) significant progress associated with new policies for reform and opening up in China from 1978 to 2000, that included contributions of Wei‐Zu Gu and other scientists. In terms of experimental hydrological findings, two notable contributions are a mathematical description of saturation overland flow derived from streamflow and precipitation data and calculated water storage deficit in the unsaturated zone by Zhao and Zhuang (1963), several years before its process‐based ‘discovery’ in the USA (and elsewhere) and the ‘interface runoff generation law’ of Yu (1985) which was ahead of its time in understanding linking the notion of the commonality of all runoff forms. In terms of model development stemming from experimental studies, the development of the Xinanjiang Model of Zhao (1980) was a significant achievement, later partly adopted into the VIC model in the USA and the ARNO model in Europe. Finally, the Hydrohill catchment developed by Wei‐Zu Gu led the way for the rapid rise in process studies and internationalization of experimental hydrology in China. Overall, the experimental hydrological studies from 1949 to 2000 had a strong engineering focus, with many links to water conservation construction and management.