Upstream Area Research Articles

Kualitas Air dan Karakteristik Tanah Penduga Erodibilitas pada Sub-Sub DAS Amandit Kabupaten Hulu Sungai Selatan

Land management in, Amandit sub-sub watershed must comply with the principles of soil and water conservation to avoid erosion and sedimentation. The aim of this research was to assess water quality and soil characteristics that predict erosion in the upstream, middle and downstream areas. The purposive sampling method was used by taking soil and water samples in the upstream, middle and downstream parts. In the upstream section soil samples were taken with a slope of 15-25%, in the middle section with a slope of 8-15% and in the downstream section with a slope of 0-8%. Soil samples were taken at each of six points representing the upstream, middle, and downstream parts of the area. Water sampling was carried out in the soil sampling area by paying attention to the slope of the land. The results showed that the water quality (pH, DHL, SAR, and TSS) in the area was in accordance with the quality of water for irrigation. Soil erodibility values in the upper and middle areas did not show significant differences. In the upstream part, soil erodibility had very low criteria and the middle part had low criteria but were different from the downstream area (medium criteria).

Watershed hydrology mediates the recovery of an arsenic impacted subarctic landscape

A holistic understanding of the chemical recovery of lakes from arsenic (As) pollution requires consideration of within-lake biogeochemical cycling of As and processes occurring in the surrounding catchment. This study used a watershed mass balance approach, complemented by experimental sediment incubations, to assess the mobility and transport of As within a subarctic watershed (155 km2) impacted by more than 60 years of atmospheric mining emissions. The period of record spanned a transition from drought to high streamflow between September 2017 and September 2019, which yielded insights into the interacting effects of hydrology and within-lake biogeochemical cycling of As. Internal loading of As from contaminated lake sediments (25–46 kg As year−1) and contributions from terrestrial sources (16–56 kg As yr−1) continue to negatively impact lake water quality (19–144 μg As L−1), but the relative importance of these loads varies seasonally and inter-annually in response to changing hydrological conditions. Wet conditions resulted in greater transport of As from terrestrial reservoirs and upstream areas, shorter lake water retention time, and increased the downstream export of As. During dry periods, the lake was disconnected from the surrounding watershed resulting in limited terrestrial contributions and longer lake water residence time, which delayed recovery due to the greater relative influence of internal loading from contaminated sediments. This study highlights that changing hydroclimatic regimes will alter trajectories of chemical recovery for arsenic impacted lakes through the coupling of within-lake and watershed transport processes.

Building MSME Competitiveness Through the Local Business Development Program in the Upstream Oil and Gas Working Area of the Rokan Block in Riau Province

This study examines the potential optimization of the Local Business Development (LBD) partnership program in the development of MSMEs in the upstream oil and gas work area of the Rokan Block, Riau Province. MSMEs in Indonesia, totaling 64.2 million units, play a crucial role in the economy by contributing 61.07% to GDP and absorbing 97% of the workforce. However, MSMEs face various challenges such as limited access to financing and low technical capabilities. Pertamina Hulu Rokan (PHR), through the LBD program, seeks to enhance the capabilities of local MSMEs in the oil and gas mining sector. This study uses the SEM-PLS analysis method to explain the relationship between partnership, entrepreneurial orientation, human resource capability, organizational learning, and the competitive advantage of MSMEs. Data were collected through questionnaires from 232 MSME owners registered in the LBD partnership program. The analysis results show that partnership, entrepreneurial orientation, and organizational learning significantly influence human resource capabilities and the competitive advantage of MSMEs. This research provides practical and theoretical guidelines for the implementation of the LBD-based partnership program, as well as deep insights for oil and gas companies, the government, and relevant stakeholders in enhancing the contribution of partnerships to MSME development. This study also bridges existing research gaps and empirical gaps and offers a new perspective on partnership theory with a local business development contract cooperation pattern supported by the upstream oil and gas company's partnership program.

Longitudinal distribution of fish fauna and characteristics of indicator species in the East Seto Inland Ecological Region within the Japanese Archipelago

Understanding biota distribution patterns is essential for ecosystem conservation and restoration. In addition to biogeography, the distribution patterns of aquatic organisms that inhabit rivers vary longitudinally along river networks. Although longitudinal changes in distribution patterns in aquatic organisms along river networks have been studied in single river basins, it is crucial to understand these patterns at a regional ecological scale for broad-scale ecosystem conservation. This study aimed to elucidate the longitudinal distribution patterns of fish fauna and their correlation with environmental factors in several watersheds within the East Setouchi Ecological Region, renowned for its rich freshwater fish diversity in the Japanese archipelago. Data were obtained for 118 species across 10 watersheds and 85 sites, and the surveyed sites were classified into four longitudinal groups based on the similarity of the fish fauna. The lowest group comprised river estuaries, abundant in brackish-water fish, comprising primarily Gobiidae species. In lower watershed areas with low agricultural land and forest cover but high urbanization, all fish species selected as indicators were non-native. Upstream areas with a high percentage of agricultural land featured a mix of native Cyprinidae and non-native species such as Micropterus salmoides and Rhodeus ocellatus ocellatus. The most upstream groups, marked by significantly greater elevations and bed slopes, exclusively comprised native species as indicator species. Analyzing the longitudinal distribution patterns of fish fauna at multiple sites within the same ecological region enabled us to choose endemic fish species as indicators and identify important species for conservation. Additionally, the selection of sites characterized by significant urbanization and strong anthropogenic influences, along with the selection of non-native species as indicators, underscores the urgency of conserving native organisms in these areas, calling for continuous monitoring.

The Relationship between the Suspended Sediment Concentration of Doab Mereg and Pol Chehr Hydrometric Stations with Vegetation in Upstream Areas Using Sentinel-2 MSI Images

The Relationship between the Suspended Sediment Concentration of Doab Mereg and Pol Chehr Hydrometric Stations with Vegetation in Upstream Areas Using Sentinel-2 MSI Images

UAV Mapping for Flood Routing in Steep and Densely Vegetated Areas: Insights from the Contok River Basin, Garang Watershed, Indonesia

This research utilizes photogrammetry to assess flood routing dynamics in the Contok river basin, a sub-watershed with a challenging landscape characterized by steep slopes, dense vegetation, and meandering patterns. The objectives are to assess Unmanned Aerial Vehicle (UAV) mapping accuracy, evaluate the river's capacity for design flood volumes, quantify the impact of land cover changes on surface runoff, and provide insights for early warning systems and watershed conservation strategies. The study area, encompassing the Contok River Basin, a sub-watershed of the Garang Watershed, covers 7,413 km² and includes a stream length of 5,274 meters in Semarang City, Central Java, Indonesia. This research employed image processing of aerial photographs and satellite imagery. Aerial photos captured using UAV data were utilized to derive elevation data and cross-sectional profiles of the Contok River, essential for understanding channel morphology and hydraulic characteristics. Concurrently, satellite imagery was used for land cover analysis, identifying vegetation and built-up areas that influence surface runoff dynamics. Hydrological analysis was performed to quantify discharge magnitudes, simulated against river cross-sections to evaluate flood behavior under varying scenarios. Our proposed UAV mapping provides adequate accuracy for small and local areas. Furthermore, it remains reliable for flood routing analysis. We discovered that the capacity of the Contok River channel in the downstream area allows it to convey design flood discharges up to a 50-year return period, contrary to the upstream area, it overflows. Notably, the shift from vegetated to built-up and agricultural areas significantly contributes to the 10.6% increase in surface runoff. This research highlights the role of UAV-based photogrammetry in assessing and mitigating flood hazards amidst evolving land cover patterns. It also enhances the understanding of flood dynamics and thus provides insights that will serve as a reference for flood early warning systems, flood management practices, and watershed conservation.

Raising environmental awareness through community-based efforts to clean and preserve the Karang Mumus river, Samarinda City

River pollution, particularly from littering, has long plagued Samarinda City. The Karang Mumus River exemplifies this challenge, with heavy downstream debris and a lack of upstream catchment areas leading to seasonal flooding. This pollution significantly reduces the community's quality of life and hinders sustainable development efforts. To address this, a community service program was initiated to raise environmental awareness through cleaning and maintaining the Karang Mumus River. The program utilized outreach methods to educate the "Save Karang Mumus" (SKM) community about the river's functions and proper environmental practices in the surrounding area. The activity culminated in a river cleaning initiative. Notably, post-program participants expressed a willingness to actively participate in future river cleaning efforts organized by GMSS-SKM. This positive outcome demonstrates the program's success in raising awareness about the importance of protecting the Karang Mumus River environment.

Local wisdom tradition of maintenance of the upstream river

Various local wisdoms are used as the center of life, obeyed, revered and given a special place by every individual. Until now, these individuals still adhere to local wisdom passed down from generation to generation as the community's cultural heritage, namely the tradition of protecting the upper reaches of the Logawa River for the people of Baseh Village. A form of local wisdom in improving community welfare by relying on the values of ancestral teachings. The aim of this research is to examine local wisdom in the maintenance and utilization of the upstream area of the Logawa River in Baseh Kedungbanteng village, Banyumas Regency, to reveal cultural character biases related to human actions related to the natural surroundings where the community resides. This research uses a case study method which focuses on one particular object to be used as a case. Baseh Village, Kedungbanteng District. Data was obtained through studying the interconnectedness of evidence from several data sources at once, namely documents, recordings, observations, open, focused and structured interviews, as well as documentation studies. The results of the research show that the true meaning is revealed, namely increasing the welfare of society both economically and for the common good. their daily needs. Research on local wisdom traditions in upstream river maintenance can be an important basis for development policies and sustainable practices in managing river ecosystems throughout the world.

GIS-Based Integrated Multi-Hazard Vulnerability Assessment in Makedonska Kamenica Municipality, North Macedonia

This study presents a comprehensive analysis of natural hazard susceptibility in the Makedonska Kamenica municipality of North Macedonia, encompassing erosion assessment, landslides, flash floods, and forest fire vulnerability. Employing advanced GIS and remote sensing (RS) methodologies, hazard models were meticulously developed and integrated to discern areas facing concurrent vulnerabilities. Findings unveil substantial vulnerabilities prevalent across the area, notably along steep terrain gradients, river valleys, and deforested landscapes. Erosion assessment reveals elevated rates, with a mean erosion coefficient (Z) of 0.61 and an annual erosion production of 182,712.9 m3, equivalent to a specific erosion rate of 961.6 m3/km2/year. Landslide susceptibility analysis identifies 31.8% of the municipality exhibiting a very high probability of landslides, while flash flood susceptibility models depict 3.3% of the area prone to very high flash flood potential. Forest fire susceptibility mapping emphasizes slightly less than one-third of the municipality’s forested area is highly or very highly susceptible to fires. Integration of these hazard models elucidates multi-hazard zones, revealing that 11.0% of the municipality’s territory faces concurrent vulnerabilities from excessive erosion, landslides, flash floods, and forest fires. These zones are predominantly located in upstream areas, valleys of river tributaries, and the estuary region. The identification of multi-hazard zones underscores the critical need for targeted preventive measures and robust land management strategies to mitigate potential disasters and safeguard both human infrastructure and natural ecosystems. Recommendations include the implementation of enhanced monitoring systems, validation methodologies, and community engagement initiatives to bolster hazard preparedness and response capabilities effectively.

Evaluasi Kapasitas Jaringan Irigasi Lanrae Pada Kebutuhan Air Sawah di Kabupaten Barru

Irrigation is an infrastructure to increase land productivity and increase the intensity of annual harvests, the availability of adequately controlled irrigation water is an input to increase crop production. The Lanrae irrigation area which has 1400 Ha of agricultural rice fields that need water, Lanrae is one of the areas located in Nepo Village, Mallusetasi District, Barru Regency. This research aims to meet the needs of irrigation water for farmers who usually experience crop failure due to lack of irrigation water and to increase the potential of existing agricultural products in the Lanrae area in particular and in Barru Regency in general as well as to overcome complaints from farmer groups who experience a lack of water to increase yields. harvest. This research was conducted in the Lanrae Area, Mallusetasi District, Barru Regency, which was carried out from January to March 2017 using quantitative methods. The results of the research on weirs and irrigation in the Lanrae area of Barru Regency showed that the availability of water in the Lanrae river is currently still sufficient to meet the needs for irrigation water in the Lanrae irrigation area and the utilization of irrigation networks for irrigation water services is not optimal and the efficiency of irrigation water use is very low. As well as the use of irrigation water in the upstream areas tends to be excessive and the use of irrigation water in the middle and even downstream areas is very short of water.

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.

The research on narrow-valley city flood control mode based on hydrodynamic-hydrological coupling model

The flood processes and control methods in narrow-valley cities exhibit significant differences compared to other regions. Therefore, precise modeling and simulation of their flood processes is crucial. This study focuses on a typical narrow-valley city located in the Loess Plateau of northern China. A hydrodynamic-hydrological coupling model was constructed to simulate the floods, analyzing flood disaster characteristics as well as the effects and differences of various flood control measures in the narrow-valley city. The results indicate: (1) The hydrodynamic-hydrological coupling model proposed in this paper is highly appropriate for accurately simulating floods in narrow-valley cities. A hydrological model was used to generalize the hydrological process in hilly mountainous areas. While a hydrodynamic model was employed to conduct a detailed simulation of the river terrace, where the main urban area is located. After validation through two actual flood events, the model demonstrated satisfactory simulation performance. (2) The flood characteristics of narrow-valley cities differ from those of plain regions mainly because the terrain restricts the spread of floods once they surpass the embankments. This limitation leads to potentially greater inundation risks in such topographical features. Additionally, the elongated distribution of cities in these areas creates spatial disparities in flooding between upstream and downstream areas. (3) There are significant variations in the effectiveness of different flood control measures. Various flood control approaches were modeled and simulated in this paper. Their flood control capabilities were ranked in descending order as: reservoirs, flood diversion channels, and river channel dredging. (4) The combined flood control effect of multiple measures is notably superior to that of individual measures. Among them, the combination of reservoirs and flood diversion channels is optimal, as it regulates the inflow from a large upstream area. The conclusions drawn in this paper can provide a certain degree of reference and basis for the construction of flood models and flood control systems in narrow-valley cities.

Impact of climate change on water crisis and conflicts: Farmers’ perceptions at the ZayandehRud Basin in Iran

Study regionThe study was conducted in the ZayandehRud Basin in Iran. Study focusConflicts over water resources have increasingly occurred on different geographic scales, linked to various human activities and environmental factors, including climate change and the water crisis. This paper examines farmers’ perceptions regarding their vulnerability to climate change, the impact of climate change on the water crisis, and water crisis-induced conflicts. The research uses meteorological data and a survey with 301 randomly selected farmers New hydrological insights for the regionFarmers confirm the significant trends and fluctuations of climatic factors by the meteorological records. Their perceptions are different within and between the upstream and downstream areas of the basin. Farmers also highlight that climate change has damaged water resources, threatened water supply, and exacerbated the water crisis. This intensifies their vulnerability, injustice, and conflicts between farmers in different sub-basins and with industry, environment, and municipal sectors. Moreover, different farmers’ perceptions regarding climate change incidence, climate change-induced water crisis, and water crisis-induced conflicts are likely to produce even greater risks of local and regional disputes among different stakeholders, unless other mechanisms for reducing water insecurity are identified and implemented. Future policies should enhance farmers’ knowledge, reduce misunderstandings and perception gaps regarding climate change and its impact on the water crisis, and manage conflicts among stakeholders and between different sub-basins through social learning platforms.

Using MODFLOW to Model Riparian Wetland Shallow Groundwater and Nutrient Dynamics in an Appalachian Watershed

Simulating shallow groundwater (SGW) flow dynamics and stream–SGW interactions using numerical modeling tools is necessary to develop a mechanistic understanding of water flow systems and improve confidence in water resource management practices. A three-dimensional (3D) SGW flow model was developed for a riparian wetland in a mixed forest and agricultural catchment in West Virginia (WV), Appalachia, USA, using a Modular 3D Groundwater Model (MODFLOW). The MODFLOW simulation was calibrated in steady (R2 = 0.98, ME = −0.21, and RMSE = 0.77), transient state (R2 = 0.97, ME = −0.41, and RMSE = 1.28) and validated (R2 = 0.97, ME = −0.28, and RMSE = 1.05) using observed SGW levels from thirteen nested piezometers under steady and transient states. An experimental MT3D transport scenario was developed to show the lateral transport of NO₃-N from the aquifer to stream cells. Relatively stable SGW head distribution was observed. In the downstream reach, SGW discharge varied from 948 m3/day to 907 m3/day in 2020, with creek seepage ranging from 802 m3/day to 790 m3/day. Similarly, SGW input to the stream ranged from 891 m3/day to 978 m3/day, while creek seepage ranged from 796 m3/day to 800 m3/day in 2021. In upstream reaches, losing stream conditions were observed in January, June, and September 2020 and January to April 2021, while gaining stream conditions prevailed during other months. Thus, an approximately monthly alternating gaining–losing stream condition was observed in the upstream area. An experimental MT3D transport scenario resulted in an advection–dispersion scenario, showing a cumulative loss of 947 g of NO3-N from SGW to the stream. Denitrification accounted for the cumulative loss of 1406 g of NO3-N from SGW, surpassing 639 g of nitrate from the SGW to the stream during the study period. Additionally, particle tracking using MODPATH indicated a long residence time for SGW nutrients, affirming the efficiency of nitrogen transformation through denitrification. This study is among the first to simulate hydrologic and nutrient interactions in riparian wetlands of a mixed land use catchment in the Appalachian region of the northeastern United States. The results better inform water resource management decisions and modeling efforts in the Appalachian region and similar physiographic regions globally.

Late Cretaceous cooling and pulsed cenozoic uplift in the Fenghuang Shan: Insights into the tectonic evolution of the Qinling Orogen, central China

Reactivation of the Qinling Orogen since the Late Jurassic has been controlled by the combined effects of the convergence between the South and North China blocks, the subduction of the Pacific Plate, and the northeastward expansion of the Tibetan Plateau. In this study, we present new apatite (U–Th)/He ages from a vertical transect in the Fenghuang Shan located in the North Daba Mountains, where rapid cooling at ∼95-90 Ma is identified. Inverse thermal history modeling results reveal another pulse of accelerated exhumation at ∼50 Ma. In addition, we analyzed longitudinal profiles of rivers draining the northern flank of the Fenghuang Shan and identified knickpoints that break channels into gentle upstream and steep downstream segments. We deduce that these knickpoints were initiated by an increase in the mountain-bounding fault throw, based on nearly constant chi values (an integral to the upstream drainage area distribution) and a reliance of knickpoints’ retreat distances on catchment areas. Assuming a linear slope exponent and erodibility of 10−6 m0.1/a, we estimated knickpoint ages to be ∼5.7 ± 1.7 Ma. We interpret the Late Cretaceous cooling as a result of lithospheric extensional collapse following the Late Jurassic intra-continental compression between the North and South China blocks. The early Cenozoic exhumation might relate to the active normal faulting, as a far-field response to the west Pacific back-arc extension. The expansion of the NE Tibetan Plateau may have triggered the late Miocene uplift of the mountain range. The multiple episodes of tectonic events in the Fenghuang Shan might correspond to various geodynamic regimes on the tectonic evolution in the Qinling Orogen.

Connecting blue-green infrastructure elements to reduce combined sewer overflows

By infiltrating and retaining stormwater, Blue-Green Infrastructure (BGI) can help to reduce Combined Sewer Overflows (CSOs), one of the main causes of urban water pollution. Several studies have evaluated the ability of individual BGI types to reduce CSOs; however, the effect of combining these elements, likely to occur in reality, has not yet been thoroughly evaluated. Moreover, the CSO volume reduction potential of relevant components of the urban drainage system, such as detention ponds, has not been quantified using hydrological models. This study presents a systematic way to assess the potential of BGI combinations to mitigate CSO discharge in a catchment near Zurich (Switzerland). Sixty BGI combinations, including four BGI elements (bioretention cells, permeable pavement, green roofs, and detention ponds) and four different implementation rates (25%, 50%, 75%, and 100% of the available sewer catchment area) are evaluated for four runoff routing schemes. Results reveal that BGI combinations can provide substantial CSO volume reductions; however, combinations including detention ponds can potentially increase CSO frequency, due to runoff prolongation. When runoff from upstream areas is routed to the BGI, the CSO discharge reductions from combinations of BGI elements differ from the cumulative CSO discharge reductions achieved by individual BGI types, indicating that the sum of effects from individual BGI types cannot accurately predict CSO discharge in combined BGI scenarios. Moreover, larger BGI implementation areas are not consistently more cost-effective than small implementation areas, since the additional CSO volume reduction does not outweigh the additional costs. The best-performing BGI combination depends on the desired objective, being CSO volume reduction, CSO frequency reduction or cost-effectiveness. This study emphasizes the importance of BGI combinations and detention ponds in CSO mitigation plans, highlighting their critical factors—BGI types, implementation area, and runoff routing— and offering a novel and systematic approach to develop tailored BGI strategies for urban catchments facing CSO challenges.

Hydraulic Dynamics of the Riparian Soil in the Chapadão do Diamante - Serra da Canastra, Minas Gerais

Serra da Canastra National Park, located in the Cerrado Biome in the State of Minas Gerais, Brazil, consolidates a conservation unit that includes the sources of several important Brazilian hydrographic basins. Given the significance of local and national water supply and regulation, this study aimed to analyze and understand the physical-hydraulic characteristics of the soil in the riparian zone within the park. Field data were collected using a rainfall simulator and a concentric ring infiltrometer. The results demonstrated an elevated infiltration capacity in the study área. Only 23.74% of the 57.4mm of artificially precipitated high-intensity rainfall was runoff. Basic infiltration velocity (BIV) values were considered very high (50.74 mm/h). Overall, these values were associated with the characteristics of the landscape, highlighting the importance of vegetation in the soil cover and the physical attributes of the soil. These factors influenced the modulation of the soil's capacity to retain, infiltrate, and store large volumes of water. In this regard, the importance of these riparian zones for the environment was emphasized as they play a crucial role in protecting watercourses. They act as barriers against erosive flow from upstream areas, incorporating water into the soil profile to store and release over time. These areas thus become important sites for water regulation.

The influence of road network topology on street flooding in New York City—A social media data approach

Urban road network is crucial stormwater infrastructure as city roads serve as paths for stormwater runoff and urban flooding. However, it remains unclear how different road networks influence urban flooding. While past studies have examined high-magnitude and high-intensity flooding events at the large river basin scale, they neglected smaller and more frequent street flooding events (SFEs) which could have a higher cumulative cost. Hence, this study used urban road network topology (RNT) factors and social media big data related to street flooding to investigate their associations with data-driven methods for 557 sewer catchments across New York City (NYC). 11,042 SFEs were taken from raw street flooding complaints (SFCs) recorded on the NYC 311 sewer complaints platform between January 1, 2010, and April 28, 2022. We then used generalized linear mixed models to identify the relationship between RNT factors and street flooding risk (SFR) and found that the characteristics of SFR periodically changed with spatial–temporal heterogeneity. While impervious factor was previously found important, RNT emerged as a new significant factor influencing SFR, with the effects being larger in combined sewer systems and heavy precipitation events. We discerned that planning a dendric road network pattern, increasing RNT connectivity in downstream areas, and having wider roads with more intersections could reduce SFR. Decreasing RNT connectivity in upstream areas, road length, the number of roads, and sewer catchment area also mitigated SFR. Our analysis provided informed street flooding mitigation and adaptation strategies to promote a more resilient, healthy, and sustainable urban environment.

Willingness to Pay for Watershed Services by Downstream Water Users in Babati District, Tanzania

Payment for Ecosystem Services promotes watershed management through Payment for Watershed Services. It encourages improved land management practices in upstream areas to enhance the quantity and quality of water downstream. The Nou Forest Reserve in Babati district covers Lake Manyara's headwaters. Its rivers are the primary water source for the area's inhabitants. However, there have been reports of declining water quality and quantity, presenting an opportunity to introduce payment for watershed services for Nou Forest Reserve conservation and management. The present study was conducted to assess the level of awareness among downstream water users about the importance of watersheds in providing sustainable water supply. Using the Contingent Valuation Method, the study estimated the communities’ willingness to pay for improved watershed services, analysed factors influencing capacity to pay, and examined possible operational modes for implementing payment mechanisms. A total of 155 domestic water users and 50 non-domestic water users were interviewed. It was found that 71% of domestic water users and 82% of non-domestic water users were willing to pay for improved watershed services, with a mean willingness to pay estimated at TAS 1261 per user/year for domestic water users and TAS 112322 per user/year for non-domestic water users. Factors such as gender, occupation, education, and farm size significantly (P<0.05) influenced water users' willingness to pay. Income was a significant factor in the willingness to pay for non-domestic water users, but it was not significant for domestic water users. The current study suggests that downstream water users in Babati district, who act as watershed service buyers, could collect a water user fee based on estimated amounts. This approach would help address declining water quality and quantity through improved watershed management and thus enhance watershed conservation and management.

Analysis of the dynamic mechanism of trans-boundary pollution collaborative control in the Yangtze River Economic Belt

Climate change mitigation requires simultaneous reduction of carbon emissions and air pollution. This study examines the synergy between pollution reduction and carbon reduction, identifying key variables and strategies to achieve this goal. Using a Geographical Detector model and a Coupling Degree of Coordination model, 108 cities in the Yangtze River Economic Belt (YREB) are investigated. Results show that while controlling PM2.5 has been more successful than managing carbon emissions in the YREB, synergy between pollution reduction and carbon emissions increased by an average of 7.2% from 2006 to 2019. Spatial analysis reveals higher synergy in upstream areas, indicating significant spatial diversity. The impact of pollution and emission reduction synergies is influenced by societal and environmental variables, including industry structure, technological innovation, energy structure, human capital quality, and economic basis. Synergy is amplified when natural limits align with high-quality development drivers such as technical innovation and the digital economy. Recommendations include enhancing city-to-city contact, improving energy and industrial structures, and fostering technological innovation to address regional variations in synergy levels.