Semi-arid River Research Articles

Assessment of groundwater suitability for drinking and irrigation purposes with probable health threats in a semiarid river basin of South India.

In the semiarid river basin of south India, the present study focuses on the appropriateness of water for drinking and irrigation as well as the risks to human health posed by pollutants. A total of 68 groundwater samples were evaluated for irrigation and consumption purposes. With a high electrical conductivity peaking at 3430 μS/cm and an alkaline composition, the groundwater has a high salinity and poor water quality. Durov's figure displays a trend along the dissolution or mixing line and identifies the geochemical facies of groundwater samples. According to water quality indexes, the majority of samples are categorized as unfit for human consumption (26.47%), extremely bad (36.76%), and poor (26.47%). According to elemental concentrations, the data are grouped into three clusters using hierarchical cluster analysis. According to the geographical distribution, nitrate levels are safe over about 320.25 km2 and dangerous over about 121.10 km2, whereas fluoride levels are safe over about 293.92 km2 and dangerous over about 147.43 km2. About 50.65 km2, 14.70% of the samples, fell into the no restriction category for irrigation, indicating acceptable standards. Low sodium levels in soils are indicated by parameters like SAR, %Na, PI, RSC, MR, and KR; SAR values fall into the C2S1, C3S1, and C4S1 categories. According to Doneen's diagram, 70.5% of samples had a PI >75, indicating suitability; the Wilcox diagram classified 22.05% of samples as excellent and 69.11% as good to permissible for irrigation. According to human health risk assessment, 75% of babies, 63% of children, 75% of teens, and 54% of adults have THI values >1 for fluoride. About 45% of newborns, 42% of kids, 45% of teenagers, and 29% of adults are at risk for nitrate. Infants, kids, and teenagers are at the danger. In order to safeguard human health against fluoride and nitrate, the study emphasizes the necessity of efficiently managing groundwater resources, lowering agricultural pollution, and assuring clean drinking water. PRACTITIONER POINTS: In the area, 79.25 km2 has good drinking water quality based on DWQI. Based on IWQI, 70.33 km2 area is recognized as suitable for agricultural practices. Geogenic and anthropogenic activities contribute to fluoride and nitrate pollution in water. Based on THI, infants and children are more prone to fluoride and nitrate contamination.

Implementation of satellite-based water accounting plus (WA+) framework for estimating groundwater balance and utilization in a semi-arid river basin of India

Implementation of satellite-based water accounting plus (WA+) framework for estimating groundwater balance and utilization in a semi-arid river basin of India

Evaluation of tourism ecological security and its obstacles in semi-arid river valley urban: a case study of Lanzhou, China

Assessing tourism ecological security is essential for balancing development with environmental sustainability, thereby guiding effective resource management and policy formulation within the tourism industry. This study evaluates the ecological security of Lanzhou’s tourism sector, a city rich in historical and natural resources yet facing unique ecological challenges. Our objectives were to assess the current status of tourism ecological security in Lanzhou and provide actionable policy recommendations. We employed a comprehensive evaluation framework that integrates both qualitative and quantitative methods, including the DPSIR model, mean square deviation, and entropy methods for weight calculation, as well as TOPSIS for overall assessment and coupled coordination degree and obstacle degree models for subsystem analysis. The results indicate an upward trend in Lanzhou’s tourism ecological security from 2009 to 2021, peaking in 2019 before experiencing a pandemic-induced decline in 2020–2021. While subsystem coupling coordination generally improved, the pressure and state subsystems exhibited instability. These findings offer valuable insights for similar regions and underscore the necessity for holistic management strategies. We recommend enhancing ecological monitoring, promoting sustainable tourism practices, and enhancing local community involvement in tourism management. These measures are crucial to improving Lanzhou’s tourism ecological security and could serve as a model for other cities with similar development trajectories. Future research should focus on refining ecological security evaluation models and exploring the broader socio-economic impacts of ecological sustainability in tourism.

Groundwater Quality and Its Suitability in the Semi-Arid River Basin in India: An Analysis of Hydrogeochemical Processes Using Multivariate Statistics

Groundwater Quality and Its Suitability in the Semi-Arid River Basin in India: An Analysis of Hydrogeochemical Processes Using Multivariate Statistics

Multivariate drought indices to analyse spatiotemporal drought propagation in a semi-arid river basin

Multivariate drought indices to analyse spatiotemporal drought propagation in a semi-arid river basin

Simulation of streamflow for extreme events using hydro-meteorological approach in the semi-arid river basin of India

Simulation of streamflow for extreme events using hydro-meteorological approach in the semi-arid river basin of India

The dynamic response of the floodplain herb Centipeda cunninghamii to managed flooding of the semi-arid River Murray

ABSTRACT River regulation can isolate the river channel from its floodplain, reducing flooding and causing vegetation to decline. Inundating isolated floodplains with environmental flows can re-invigorate natural vegetation suffering from hydrologic alteration. The floodplain between Locks 5 and 7 along the lower River Murray in South Australia was inundated in summer 2005–2006 by a managed weir-pool surcharge. We observed a highly variable response to inundation in the frequency and spatial distribution of the perennial floodplain herb, Centipeda cunninghamii (common sneeze-weed). Generally, there was little change in C. cunninghamii abundance or distribution prior to the surcharge. At most sites, C. cunninghamii frequency declined immediately after the surcharge, presumably as existing plants died due to prolonged inundation. At one site, C. cunninghamii did not recover and disappeared. At the other sites, C. cunninghamii re-grew, either in the same location as it was prior to the surcharge, or on a different part of the floodplain. However, at these latter sites, C. cunninghamii tended to recolonise its original location in less than two years. The use of regulatory structures to reconnect river-floodplain ecosystems should be used more widely as this can have a positive environmental impact by altering both floodplain vegetation frequency and distribution.

Health hazards from perchlorate enriched groundwater of a semi-arid river basin of south India and suggesting in-situ remediation through Managed Aquifer Recharge

The present study was conducted to assess the groundwater quality and perchlorate contents in the pre- and post-monsoon groundwater samples along with its associated health concerns with suggesting in-situ remediation in semi-arid Arjunanadi River basin of south India. Most of the samples (86 in pre-monsoon and 84 in post-monsoon out of total 94) showed secondary salinity and secondary alkalinity, and the perchlorate showed positive relations with Na+, K+, SO42-, Cl-, and NO3- contents. The main source of perchlorate could be fireworks manufacturing industries with 23 % of pre-monsoon (246.5 km2) and 33 % of post-monsoon samples (360 km2) showing perchlorate above the World Health Organization (WHO) standard (>0.07 mg/l). Perchlorate health risk assessment (PHRA) and total hazard index (THI) indicated more effect from oral pathway compared to the dermal pathway with about 80 %, 79 %, 65 %, and 60 % of samples causing health complications for infants, children, women, and men during the pre-monsoon. The post-monsoon groundwater showed increased health risks with 90 %, 82 %, 74 %, and 69 % of samples remaining hazardous for infants, children, women, and men. Artificial recharge through Managed Aquifer Recharge (MAR) techniques in the high-risk area could be useful to minimize the perchlorate contamination in groundwater and associated health risks under the United Nations Development Programme (UNDP) Sustainable Development Goals 3 and 6 (SDGs) for a healthy society.

Optimizing sustainable development in arid river basins: A multi-objective approach to balancing water, energy, economy, carbon and ecology nexus

The ongoing water crisis poses significant threats to the socioeconomic sustainability and ecological security of arid and semi-arid river basins. Achieving Sustainable Development Goals (SDGs) within a complex socio-ecological nexus requires effective and balanced resource management. However, due to the intricate interactions between human societies and environmental systems, the tradeoffs and synergies of different SDGs remain unclear, posing a substantial challenge for collaborative management of natural resources. Here we introduce a gray fractional multi-objective optimization (GFMOP) model to balance multi-dimensional SDGs through a novel water–energy–economy–carbon–ecology nexus perspective. The model was applied to a typical arid river basin in Northwest China, where thirty-two scenarios were explored, considering factors such as shared socioeconomic pathways, carbon removal rates, water conveyance efficiencies, and ecological requirements. The results reveal a strong tradeoff between marginal benefit and carbon emission intensity, indicating that improving the economic efficiency of water use can simultaneously reduce emissions and protect the environment. Given the immense power generation potential, wind power development should be prioritized in the future, with its share in the energy structure projected to increase to 23.3% by 2060. Furthermore, promoting carbon capture technologies and expanding grassland coverage are recommended to achieve regional carbon neutrality, contributing 39.5% and 49.1% to carbon absorption during 2021–2060, respectively. Compared with traditional single-objective models, GFMOP demonstrates a superiority in uncovering interrelationships among multiple SDGs and identifying compromised alternatives within the compound socio-ecological nexus. The model also provides detailed strategies for resource allocation and pollutant control, offering valuable guidance to policymakers and stakeholders in pursuing sustainable and harmonious watershed management.

Semi-arid rather than arid regions of China deserve the priority in drought mitigation efforts

The integration of drought assessment, mitigation priority analysis and mitigation measures development is a forward-looking strategy to achieve water resources allocation, implement anti-drought techniques and formulate corresponding mitigation measures strategies. However, since most drought indices cannot be based on surface water-balance to estimate water demand for drought recovery, there is a gap between drought assessment and proactive drought mitigation. Here, we established the Standardized Water Availability Index (taking water yield as surface water deficit/surplus) to identify hydrological drought, and further use it to determine the water demand for hydrological drought mitigation. On that basis, a comprehensive framework, integrating with drought assessment-resilience-recovery and water scarcity stress, was proposed to investigate the hydrological drought mitigation priority for basins in different climate regions in China. The results show that non-humid river basins have greater water scarcity stress, lower resilience to hydrological drought, but less water demand for hydrological drought mitigation (3 mm ∼ 7 mm in mild drought, 5 mm ∼ 14 mm in moderate drought, 7 mm ∼ 21 mm in severe drought). In contrast, humid river basins have greater water demand for hydrological drought mitigation (15 mm ∼ 49 mm in mild drought, 27 mm ∼ 93 mm in moderate drought, 32 mm ∼ 119 mm in severe drought), but higher resilience to hydrological drought. The densely populated semi-arid river basins in China should be given priority attention in mitigating hydrological drought on account of their greatest water scarcity stress, lower drought resilience, and less water demand for drought mitigation. This work highlights the complexity of the hydrological drought mitigation, and our findings can help stakeholders to make precise drought mitigation measures and adapt drought-relative water management.

Drought evaluation using various evapotranspiration models over semi-arid river basins

ABSTRACT Multivariate drought indices including various hydrological processes into account can be more valuable under climatic and anthropogenic changes. Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized precipitation Actual Evapotranspiration Index (SPAEI) are the drought indices used to estimate drought index, considering precipitation, and evapotranspiration (ET) into account. Many studies used empirical, machine learning, and process-based model estimates of ET for the calculation of drought indices of SPEI and SPAEI. However, the sensitivity of ET estimates on drought characteristics at the catchment scale is highly complex. The present study aimed to include and analyze the sensitivity of various approaches of empirical (Budyko, Penman–Monteith, Hargreaves, and Turc), modeled (SWAT), and remote sensing (MODIS) in the drought characterization using SPEI and SPAEI. The present methodology was tested on a dry-sub-humid river catchment of India, the Tunga-Bhadra River catchment for the period of 2000–2012. The performance of statistical indicators (Nash–Sutcliffe Efficiency and R2) for SPEI values by various empirical methods of Potential Evapotranspiration (PET) (i) Penman–Monteith (ii) Hargreaves against remote sensing PET were 0.93 and 0.95, respectively, which are high in comparison with SWAT simulated PET-based SPEI values, which shows NSE values of 0.85 against remote sensing PET-based SPEI.

The Response of Carbonate System to Watershed Urbanization Process in a Semi-Arid River

The Response of Carbonate System to Watershed Urbanization Process in a Semi-Arid River

Comparative evaluation of meteorological and hydrological drought using stationary and non-stationary indices in a semi-arid river basin in India

Comparative evaluation of meteorological and hydrological drought using stationary and non-stationary indices in a semi-arid river basin in India

Evaluation of the impact of anthropogenic storage on the hydrological drought propagation in two contrasting semi-arid river basins

ABSTRACT This study quantitatively investigated reservoir-effects on drought propagation in two semi-arid river basins: India’s Tapi basin with the Ukai reservoir and Uzbekistan’s Chirchik basin with the Charvak reservoir. Meteorological drought (MD) is analyzed using the Standardized Precipitation Index (SPI) and hydrological drought (HD) using the Standardized Streamflow Index (SSI) for the duration from 1980 to 2004. Both the river basins, especially in upstream reservoir areas, exhibited a notable correlation between HD and MD. Reservoir operation was observed to reduce the downstream MD–HD correlation at shorter SPI timescales. Hit-score-based evaluations indicated that reservoir operation has induced changes in the drought propagation patterns for both river basins. Due to the contrasting characteristics, the river basins showed a significant variation in the drought propagation time (DPT), with distinct influences from monsoon (Tapi) and snow-melting (Chirchik). The average DPT (average DPT over 12 months) for the reservoir-influenced part of the Tapi (∼ six months) and Chirchik (∼ nine months) basins is higher than that of the natural parts of both basins (Tapi: ∼ four months; Chirchik: ∼ six months) as a result of the natural and anthropogenic storage influence.

Hydrological response to vegetation restoration and urban sprawl in typical hydrologic years within a semiarid river basin in China

Hydrological response to vegetation restoration and urban sprawl in typical hydrologic years within a semiarid river basin in China

Vegetation greening accelerated hydrological drought in two-thirds of river basins over China

Although the vegetation-greening-induced water supply reduction has been widely recognized, little is known about the impacts of vegetation greening on hydrological drought. Here Standardized Water Availability Index (SWAI, based on surface water-balance), driven by evapotranspiration (ET, with vegetation dynamics), was developed to quantify the impacts of vegetation greening on hydrological drought at multiple timescales over China from 1982 to 2015. The ET with vegetation dynamics was modeled by the improved PT-JPL model, and was validated with in-situ observed data from 8 flux tower sites and 4 on-site field experiments (covered with 12 different land-cover types in China). SWAI was also validated with monthly runoff records (from 59 gauging stations over different climatic regimes in China), and proved to effectively capture the response of water surplus/deficit to vegetation dynamics. Results reveal that percentage drought-affected areas increased (increased by 2 % to 9 %) and drought intensity enhanced in two-thirds of Chinese river basins due to vegetation greening. Moreover, in nearly half of the river basins in China, drought duration increased by 0.035–0.131 months, and drought frequency increased by 0.016–0.085 months/34-year. Hydrological drought accelerated by vegetation greening mainly occurred in arid and semi-arid river basins (water-limited areas), while it was not obvious in humid and sub-humid river basins due to limited energy for ET in these areas. Our work and findings provide new insights for understanding the vegetation-induced water resource shortage and have potential applications for government and water managers to timely monitor and assess the balance between ecological restoration and water resources.

BHARAT: a MADM approach to prioritizing the best performing EPS in a semi-arid river basin

BHARAT: a MADM approach to prioritizing the best performing EPS in a semi-arid river basin

Assessment of machine learning models to predict daily streamflow in a semiarid river catchment

Assessment of machine learning models to predict daily streamflow in a semiarid river catchment

Assessment of climate change impact and comparison of downscaling approaches: a case study in a semi-arid river basin

Assessment of climate change impact and comparison of downscaling approaches: a case study in a semi-arid river basin

Flood dynamics on the upper Letaba River, South Africa, deduced from luminescence dating

ABSTRACT The Letaba River is one of several east-flowing rivers in the semiarid region of northeast South Africa. There is strong seasonality of river discharge and patterns of geomorphic behaviour along bedrock- and sediment-dominated reaches in these rivers, and in response to extreme seasonal flood events. This paper presents new luminescence ages on sediment samples from five sites in upper (headwater) reaches of the Letaba River catchment outside of Kruger National Park, South Africa, combined with evidence from reach-scale geomorphology and sediment sample analysis. River reaches are mainly mixed bedrock-alluvial with a patchwork of poorly sorted coarse sand bars overlying an abraded extended bedrock channel system. Luminescence ages from river sediment deposits (n = 13) cluster around three time periods of the last 400 years, 500–1100 BP, and 1400 BP. This suggests different reworked populations are present, which are a result of the partial bleaching of quartz grains and, thus, a mixed luminescence signal as flood-transported sediments are progressively moved from one depositional sink to another. This pattern of luminescence ages is quite different to lowland river systems in the same region where ages on the whole are significantly younger. Flood processes and dynamics in headwater reaches of semiarid rivers are often not considered but can yield a better understanding of system sensitivity to climate and event forcing.