Minjiang River Basin Research Articles

Efficiency evaluation with feedback for regional water use and wastewater treatment

Clean water is crucial for sustainable economic and social development; however, around the world low water use efficiency and increasing water pollution have become serious problems. To comprehensively evaluate water use and wastewater treatment, this paper integrated bi-level programming (BLP) and Data Envelopment Analysis (DEA) with a feedback variable to deal with poor output to rank DMUs using a super efficiency DEA. The proposed model was applied to a case study of 10 cities in the Minjiang River Basin to demonstrate the applicability and effectiveness, from which it was found that a water system can only be cost-efficient when both the water use and wastewater treatment subsystems are both cost-efficient. The comparison analysis demonstrated that the proposed model was more discriminating, and stable than traditional DEA models and was able to better improve total water system cost efficiencies than a BLP-DEA model.

An estimate of human and natural contributions to changes in water resources in the upper reaches of the Minjiang River

Climate change and human activities have changed the spatial-temporal distribution of water resources, especially in a fragile ecological area such as the upper reaches of the Minjiang River (UMR) basin, where they have had a more profound effect. The average of double-mass curve (DMC) and Distributed Time-Variant Gain Hydrological Model (DTVGM) are applied to distinguish between the impacts of climate change and human activities on water resources in this paper. Results indicated that water resources decreased over nearly 50 years in the UMR. At the annual scale, contributions of human activities and climate change to changes in discharge were −77% and 23%, respectively. In general, human activities decreased the availability of water resources, whereas climate change increased the availability of water resources. However, the impacts of human activities and climate change on water resources availability were distinctly different on annual versus seasonal scales, and they showed more inconsistency in summer and autumn. The main causes of decreasing water resources are reservoir regulation, and water use increases due to population growth. The results of this study can provide support for water resource management and sustainable development in the UMR basin.

Surface runoff response to climate change based on artificial neural network (ANN) models: a case study with Zagunao catchment in Upper Minjiang River, Southwest China

Abstract Climate change and its hydrological consequences are of great concern for water resources managers in the context of global change. This is especially true for Upper Minjiang River (UMR) basin, where surface runoff was reported to decrease following forest harvesting, as this unusual forest–water relationship is perhaps attributed to climate change. To quantify the hydrological impacts of climate change and to better understand the forest–water relationship, an artificial neural network (ANN)-based precipitation–runoff model was applied to Zagunao catchment, one of the typical catchments in UMR basin, by a climate scenario-based simulation approach. Two variables, seasonality and CTsm (cumulative temperature for snow melting), were devised to reflect the different flow generation mechanisms of Zagunao catchment in different seasons (rainfall-induced versus snow melting-oriented). It was found that the ANN model simulated precipitation–runoff transformation very well (R2 = 0.962). Results showed runoff of Zagunao catchment would increase with the increase in precipitation as well as temperature and such a response was season dependent. Zagunao catchment was more sensitive to temperature rise in the non-growing season but more sensitive to precipitation change in the growing season. Snow melting-oriented runoff reduction due to climate change is perhaps responsible for the unusual forest–water relationship in UMR basin.

The Influence of Eco-water Retrieved by Quantitative Remote Sensing on Runoff in Upper Minjiang River Basin

Remote sensing quantitative retrieval of ecological water (eco-water) has been foundational in systemic and quantitative research for water resources. Eco-water resource levels indicate conservation ability for the eco-water layer and influence of this on precipitation transformation and runoff regulation. The remote sensing quantitative inversion retrieved the MEC (Modulus of eco-water Conservation) of the Upper Minjiang River Basin study area in 1994 and 2001, and combined with climate data between 1990 and 2005, the influence of conservation water on the eco-water layer on runoff was then analyzed. Results revealed significant efficacy for flood control and water supply during the drought from the hydrologic cycle of ecowater. Thus protection and restoration of the eco-water layer for flood and drought prevention are crucial. Influencia del agua ecológica en la escorrentía de la cuenca alta del río Minjiang medida a través de teledetección cuantitativa ResumenEl sondeo remoto del agua ecológica (del inglés Eco-water, agua conservada en la superficie terrestre) es indispensable en la investigación sistemática y cuantitativa de las fuentes de agua. Los niveles de suministros de agua ecológica indican la capacidad de conservación de la capa de agua ecológica y la influencia de esta en la transformación de precipitación y la regulación de escorrentía. La inversión cuantitativa por sondeo remoto estableció el Módulo de Conservación de Agua Ecológica (MEC, del inglés Modulus of Eco-Water Conservation) para el área de estudio en la cuenca alta del río Minjiang entre 1994 y 2001, y combinada con la información climática de entre 1990 y 2005, se analizó la influencia de conservacion de agua en la capa ecoacuática. Los resultados mostraron una gran eficacia en el control de inundaciones y en el suministro de agua durante la sequía a lo largo del ciclo hidrológico. Por esta razón, la protección y restauración de la capa de agua ecológica para la prevención de inundaciones y sequía es necesaria.

Model of Eco-Water Driving Force Affecting the Evolvement of Runoff in the Upper Minjiang River Basin

Abstract The amount of eco-water resources reflects the land surface water conservation capability, and the underlying surface condition in the hydrologic cycle. In the upper Minjiang River Basin, the amounts of eco-water resources were retrieved from remotely sensed data during 1992 to 2005. Through regression analysis between the retrieved eco-water data and the climate hydrological data mainly including the temperature, the precipitation, and the runoff in the same period, the model of eco-water driving force affecting the evolvement of runoff was established. The accuracy analysis indicates that the model can well describe the relationship between dry season runoff and its driven factors, the measured data validation proves that the model has high precision and good practicability. The eco-water remote sensing inversion provides a valid method to quantify the land surface water conservation capability, and suggests an interesting approach for the driving function quantitative researches of underlying surface factor in the hydrologic cycle.

Flood/drought event identification using an effective indicator based on the correlations between multiple time scales of the Standardized Precipitation Index and river discharge

In order to further investigate the capability of the Standardized Precipitation Index (SPI) to identify flood/drought events, monthly precipitation data from 26 precipitation stations and monthly discharge data from four hydrological stations from 1960 to 2006 in the Minjiang River basin were used to analyze the correlations between multiple time scales of the SPI and river discharge. The SPI series that had a maximum correlation with discharge was chosen to detect flood/drought events in the basin, and the results were compared to historical flood/drought events. The results indicated the following. (1) High Pearson correlations between the SPI and discharge were identified at shorter time scales (1 to 3 months), and the maximum correlation was found on the time scale of 2 months. (2) Five floods among the six largest historical flood events in the Minjiang River basin were identified with the 2-month SPI, but the SPI does have shortcomings in identifying more general floods. The SPI also identified major drought events that were consistent with historical data. This demonstrates that the 2-month SPI is an effective indicator for the identification of major flood/drought events in the Minjiang River basin.

Observed changes in precipitation extremes across 11 basins in China during 1961–2013

ABSTRACTExtremes of weather and climate can cause disasters such as floods and droughts. Further studies of precipitation extremes are crucial for enabling reliable projections of future changes. In this study, we used a high‐resolution (0.5° × 0.5°) gridded precipitation data set to analyse these events across the 11 basins in China between 1961 and 2013 mainly by the Mann–Kendall and generalized extreme value methods. Our results indicated a wetter trend in the Tarim River Basin (TRB) but drier conditions in the central Yangtze River Basin (YRB), western Pearl River Basin and eastern Yarlung Tsangpo River Basin. There was an increasing risk of flooding in the mid‐lower YRB and Minjiang River Basin (MRB), and an increasing risk of drought in the central Lantsang River Basin. The results revealed strengthened maximum 1‐day precipitation (RX1DAY) in the Liaohe River Basin (LB), YRB, MRB and TRB, together with strengthened maximum 5‐day precipitation (RX5DAY) in the Songhua River Basin, MRB and TRB during 1987–2013. RX1DAY and RX5DAY for return periods of 20 and 50 years gradually decreased from southeast to northwest. Along the south‐eastern coastline of the Mainland and on Hainan Island, the RX1DAY for the 20‐ and 50‐year return periods would exceed 165 and 195 mm, respectively, whereas the RX5DAY would exceed 270 and 320 mm for the same return periods. Furthermore, summer Southern Oscillation Index (SOI) positively impacted precipitation extremes in the Yellow River Basin and YRB, and autumn SOI negatively impacted the extremes of the next year in LB and YRB, while winter SOI negatively impacted the extremes of the next year in YRB. Additionally, the East Asia summer monsoon (EASM) and the South Asia summer monsoon (SASM) were both associated with precipitation extremes across China; however, EASM contributed more to these events than did the SASM.

Application of the PRMS model in the Zhenjiangguan watershed in the Upper Minjiang River basin

Abstract. The PRMS model was established for Zhenjiangguan watershed in the upper reach of the Minjiang River basin, China. The results showed that PRMS had an acceptable performance in simulating monthly runoff in the study area. The analysis on the impacts of precipitation changes on hydrological processes indicated that both runoff and evapotranspiration increased with the increase of precipitation. Moreover, evapotranspiration had larger sensitivity to the change of precipitation than runoff.

Options and strategies for livelihood sustainability in mountainous region of the upper Minjiang River basin, Sichuan Province, China

Options and strategies for livelihood sustainability in mountainous region of the upper Minjiang River basin, Sichuan Province, China

Evaluation of environmental vulnerability in the upper reaches of the Minjiang River

With TM remote sensing data and topographic data as the main data sources,coupled with other statistical information obtained in the upper reaches of Minjiang River,the authors tried to apply the analytic hierarchy process( AHP) to reframing the vulnerability characteristics resulting from complicated factors and establishing the comprehensive evaluation index system and the model with multiple objective elements. Vegetation index change rate,population density,terrain relief,slope and soil type were five factors serving as evaluation index factors in the AHP to determine the weight of each evaluation index,and superimposition analysis of the indicators was made on the Arc GIS platform. The grade map of comprehensive evaluation on ecological environment in the reaches of the Minjiang River could be obtained,which was classified into five degrees in the environmental vulnerability. The results achieved by the authors indicate that environmental vulnerability of the upper reaches of the Minjiang River is extremely intense,caused mainly by natural factors and human factors. The results of his study provide the quantitative and qualitative scientific basis for the construction of the environmental vulnerability pattern and the comprehensive evaluation of ecological environment along the upper reaches of the Minjiang River basin.

The source of natural and anthropogenic heavy metals in the sediments of the Minjiang River Estuary (SE China): Implications for historical pollution

Two sedimentary cores in the Minjiang River estuary (SE China) are documented for grain size, clay minerals, heavy metals, magnetic parameters and Pb isotopes to investigate the source and historical variation of heavy metals. The MJK9 core was collected outside of the Minjiang River estuary, and the core is composed of mixed sediments, of which ~70% from the Yangtze River and 30% from the Minjiang River. It is thus difficult to be used for tracing the human activity along the Minjiang River. In contrast, the sediments of MJK16 core which was collected in a nearshore area are primarily from the Minjiang River. The enrichment factors of the sediments were <1.5, indicating minor pollution. The results indicate that the sediments of the MJK16 core have Cu and Pb concentrations increasing since 1980, associated with the increase of magnetic mineral concentration and 206Pb/207Pb and 206Pb/208Pb of the sediments. We compared the Pb isotopic compositions between our results and those for the deposit mining in the Minjiang River basin, and aerosols and coal dust in south China, and considered that Pb in the sediments of the MJK16 core was derived primarily from weathered rocks as well as industrial emission (e.g. coal combustion). The sediments have anthropogenic Pb concentrations ranging from 6% in 1950 to 23.7% in 2010, consistent with the impact of rapid urban and industrial development in China.

Dilution of 10Be in detrital quartz by earthquake-induced landslides: Implications for determining denudation rates and potential to provide insights into landslide sediment dynamics

The concentration of 10Be in detrital quartz (10Beqtz) from river sediments is now widely used to quantify catchment-wide denudation rates but may also be sensitive to inputs from bedrock landslides that deliver sediment with low 10Beqtz. Major landslide-triggering events can provide large amounts of low-concentration material to rivers in mountain catchments, but changes in river sediment 10Beqtz due to such events have not yet been measured directly. Here we examine the impact of widespread landslides triggered by the 2008 Wenchuan earthquake on 10Beqtz in sediment samples from the Min Jiang river basin, in Sichuan, China. Landslide deposit material associated with the Wenchuan earthquake has consistently lower 10Beqtz than in river sediment prior to the earthquake. River sediment 10Beqtz decreased significantly following the earthquake downstream of areas of high coseismic landslide occurrence (i.e., with greater than ∼0.3% of the upstream catchment area affected by landslides), because of input of the 10Be-depleted landslide material, but showed no systematic changes where landslide occurrence was low. Changes in river sediment 10Beqtz concentration were largest in small first-order catchments but were still significant in large river basins with areas of 104–105 km2. Spatial and temporal variability in river sediment 10Beqtz has important implications for inferring representative denudation rates in tectonically active, landslide-dominated environments, even in large basins. Although the dilution of 10Beqtz in river sediment by landslide inputs may complicate interpretation of denudation rates, it also may provide a possible opportunity to track the transport of landslide sediment. The associated uncertainties are large, but in the Wenchuan case, calculations based on 10Be mixing proportions suggest that river sediment fluxes in the 2–3 years following the earthquake increased by a similar order of magnitude in the 0.25–1 mm and the <0.25 mm size fractions, as determined from 10Beqtz mixing calculations and hydrological gauging, respectively. Such information could provide new insight into sediment transfer, with implications for secondary sediment-related hazards and for understanding the removal of mass from mountains.

Vegetation distribution pattern along altitudinal gradient in subtropical mountainous and hilly river basin, China

Knowledge of vegetation distribution patterns is very important. Their relationships with topography and climate were explored through a geographically weighted regression (GWR) framework in a subtropical mountainous and hilly region, Minjiang River Basin of Fujian in China. The HJ-1 satellite image acquired on December 9, 2010 was utilized and NDVI index was calculated representing the range of vegetation greenness. Proper analysis units were achieved through segregation based on small sub-basins and altitudinal bands. Results indicated that the GWR model was more powerful than ordinary linear least square (OLS) regression in interpreting vegetation-environmental relationship, indicated by higher adjusted R2 and lower Akaike information criterion values. On one side, the OLS analysis revealed dominant positive influence from parameters of elevation and slope on vegetation distribution. On the other side, GWR analysis indicated that spatially, the parameters of topography had a very complex relationship with the vegetation distribution, as results of the various combinations of environmental factors, vegetation composition and also anthropogenic impact. The influences of elevation and slope generally decreased, from strongly positive to nearly zero, with increasing altitude and slope. Specially, most rapid changes of coefficients between NDVI and elevation or slope were observed in relatively flat and low-lying areas. This paper confirmed that the non-stationary analysis through the framework of GWR could lead to a better understanding of vegetation distribution in subtropical mountainous and hilly region. It was hoped that the proposed scale selection method combined with GWR framework would provide some guidelines on dealing with both spatial (horizontal) and altitudinal (vertical) non-stationarity in the dataset, and it could easily be applied in characterizing vegetation distribution patterns in other mountainous and hilly river basins and related research.

Employing DPSIR Conceptualization and PP Clustering Algorithm to Predict Water Resources Carrying Capacity of River Basins in Fujian, China, in 2020

Water resources carrying capacity (WRCC) is very significant to the sustainable developing of society and ecosystem. The main goal of this paper was to predict WRCC of river basins in Fujian province, using index-set method, to provide a adjuvant reference for the planning department while making decisions. Under the guidance of DPSIR framework, 20 indices in total were selected, which can reflect the inherent attributes of WRCC. PP Clustering (PPC) model coupled with generic algorithm was applied to compute WRCC ranking. This model can automatically identify the contribution of every factor to the evaluating objective, as to avoid the subjectivity during the process of index weights. The predictive result shows WRCC of the southeastern area of Fujian is in relative better state of water resources utilization. Special attention needs to be paid to optimum allocation for water resources in the upper reaches area of Minjiang River basin and northeastern area.

Vegetation restoration patterns and their relationships with disturbance on the Giant Panda Corridor of Tudiling, Southwest China

Human activities such as deforestation, cultivation, and overgrazing have contributed to the destruction of forest ecosystems in the upper Minjiang River basin for a long time, which has led to the reduction in forest coverage and biodiversity. On the Giant Panda Corridor of Tudiling in this basin, the effects of the existing disturbance regimes on plant communities after the vegetation restoration in the 1980s were assessed, and the community composition, the species diversity and their relationships with environmental factors significantly associated with the disturbance were analyzed using the transect sampling method, the two-way indicator species analysis (TWINSPAN) and the detrended canonical correspondence analysis (DCCA). The results were as follows: communities could be classified into six types, and species were clustered into four functional groups (responsive to disturbance, retarded disturbance, resistant to intermediate disturbance, and resistant to heavy disturbance) based on both TWINSPAN and DCCA. DCCA with species composition of plots is similar to that with species diversity of plots. The communities were separated into distinct groups along the DCCA axis, and this pattern was significantly correlated with environmental factors. Elevation differences, shape, slope, distance to roads, and the number of paths in the plots had an evident influence on the distribution of the species and communities. Environmental factors including slope, distance to roads, and the number of paths revealed the gradient of disturbance among the communities along the DCCA axis. High disturbance intensity caused significantly lower species diversity and inhibited the regeneration of vegetation compared with the more diverse undisturbed communities. Artificial restoration was more effective than natural restoration in maintaining high species diversity. The process of succession was inhibited in natural restoration because of the failure of tree establishment, growth, and survival during regeneration.

GIS-based spatial analysis and modeling for landslide hazard assessment: A case study in upper Minjiang River basin

By analyzing the topographic features of past landslides since 1980s and the main land-cover types (including change information) in landslide-prone area, modeled spatial distribution of landslide hazard in upper Minjiang River Basin was studied based on spatial analysis of GIS in this paper. Results of GIS analysis showed that landslide occurrence in this region closely related to topographic feature. Most areas with high hazard probability were deep-sheared gorge. Most of them in investigation occurred assembly in areas with elevation lower than 3 000 m, due to fragile topographic conditions and intensive human disturbances. Land-cover type, including its change information, was likely an important environmental factor to trigger landslide. Destroy of vegetation driven by increase of population and its demands augmented the probability of landslide in steep slope.

Landscape Changes from 1974 to 1995 in the Upper Minjiang River Basin, China

Landscape changes were traced over the 20 years from 1974 to 1995 in the upper Minjiang River basin, one of the most important forest regions in China, based on satellite image interpretation to provide basic data for local decision-making as well as sustainable landscape use and management. Results revealed that landscape from 1974 to 1995 changed at the regional scale as the area of forestland decreased, while cropland, shrubland, economic forest, grassland, and built-up land increased. Landscape changes mainly occurred in forestland, shrubland, grassland, economic forest, and built-up land. Moreover, the changes among forestland, shrubland, and grassland were the largest, influencing the whole characteristics of the changes in the basin. Analysis of the changes between 1974 and 1995 in the study area indicated that landscape heterogeneity and fragmentation increased, whereas landscape connectivity decreased. There were multiple reasons for landscape changes. A principal component analysis (PCA) was used to quantitatively study driving forces of landscape changes. The PCA results showed that economic and population factors were the principal driving forces of landscape changes from 1974 to 1995 in the upper Minjiang River basin, and that PCA was a suitable method for investigating driving forces of landscape changes.

Differential responses of shrubs and herbs present at the Upper Minjiang River basin (Tibetan Plateau) to several soil variables

Vertical structure in plant communities is well recognized, but questions remain about the response of different stratal layers in a plant community to resource use. This study provides a quantitative approach to compare the relationships of nine edaphic factors and species distributions in shrub and herb layers, respectively, in an arid valley of the upper Minjiang River, Sichuan Province, China. Classification (TWINSPAN) determined three groups of shrubs and four groups of herbs. Ordination (both DCA and DCCA) found a correlation among species and edaphic variables. Borcard's method [Borcard, D., Legendre, P., Drapeau, P., 1992. Partialling out the spatial component of ecological variation. Ecology 73, 1045–1055.] was employed to partition the variation of species abundance data into independent components: pure spatial, pure environmental, spatial component of environmental influence, and undetermined. Based on those four components, a quantitative comparison of ecological variation between shrubs and herbs further eluidated their different response to the environment. Although soil moisture (SM) content, pH, soil organic matter (OC) and available potassium (AK) were the most important factors to both, the explained ecological variation of herbs was lower than that of shrubs. Understanding differences between stratal layers in resource use can shed light on plant–environment relationships.