Researches on Temporal and Spatial Changes of Suspended Sediment Nutrients and Source Contributions in Xitiaoxi River, China

2014 ◽  
Vol 955-959 ◽  
pp. 3259-3265
Author(s):  
Zhao Peng Lu ◽  
Xu Yin Yuan ◽  
Hai Long Chen ◽  
Huan Wang ◽  
Xue Qiang Zhao
Keyword(s):  
Land Use ◽  
Suspended Sediment ◽  
Arable Land ◽  
Urban Land ◽  
Dry Season ◽  
Wet Season ◽  
Material Source ◽  
Sediment Nutrients ◽  
Geochemical Parameters ◽  
Temporal And Spatial

Xitiaoxi River is the main discharge river of Taihu Lake. It is important to research changes of suspended sediment nutrients and their provenances for the water environment management. This paper analyzes temporal and spatial variations of nutrients in suspended sediments (SS) and establishes the geochemical model to quantify the proportions of SS sources with geochemical parameters in different reaches. The results show that the contents of SS and its nutrients of the downstream are significantly higher than the upstream and midstream. The contents of nutrients in SS in dry season are higher than in wet season. The C/N and IP/OP ratios of SS can effectively reflect the material source types in the different reaches, which are associated with land use types. Woodland is relatively higher contribution to SS in the upstream, arable lands become a major contributor to SS in the midstream, while urban land is the highest contribution to SS in the downstream. Seasonal changes also affect the contributions of land use to SS. Woodland and urban land show more contributions to SS in wet season than in dry season, whereas arable land and bank sediment show the higher proportions for SS source.

Comparative Researches on the Provenances of Suspended Sediments in Different Reaches of Dongtiaoxi and Xitiaoxi Watershed

2014 ◽  
Vol 937 ◽  
pp. 597-603
Author(s):  
Zhao Peng Lu ◽  
Xu Yin Yuan ◽  
Huan Wang ◽  
Hai Long Chen ◽  
Wen Wen Xu
Keyword(s):  
Taihu Lake ◽  
Arable Land ◽  
Suspended Sediments ◽  
Urban Land ◽  
Dry Season ◽  
Wet Season ◽  
Geochemical Model ◽  
Geochemical Parameters ◽  
Main Discharge ◽  
The Difference

Dongtiaoxi and Xitiaoxi river are the two main discharge rivers of Taihu Lake. It is important to research the provenances of suspended sediments (SS) and the difference of the provenances. This paper establishes the geochemical model to quantify the proportions of SS sources with geochemical parameters, and then analyzes the contribution differences of the sources to SS in the basins and its reasons. The results show that the contribution of woodland is highest in the upper reaches of both Dongtiaoxi and Xitiaoxi basin, but the contribution of arable land has more differences. Arable land becomes a major contributor to the midstream of Dongtiaoxi and Xitiaoxi basin, while the contributions of woodland and urban land are larger in Dongtiaoxi basin. The SS contribution of urban land is highest in the downstream of Dongtiaoxi and Xitiaoxi basin, while the contribution of arable land is larger in Dongtiaoxi basin. During wet season and dry season, the differences of the sources contribution variations in Dongtiaoxi basin are not obvious, while that in Xitiaoxi basin are significantly obvious, that is the SS contributions of woodland and urban land in wet season are significantly higher than in dry season, while the contributions of arable land and bank sediment are on the contrary.

scholarly journals Pemetaan Indek Kekeringan dan Sebaran Titik Hotspot Daerah Potensi Kebakaran Hutan dan Lahan di Propinsi Riau

2018 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Yotta Autika ◽  
Aras Mulyadi ◽  
Yusni Ikhwan Siregar
Keyword(s):  
Land Use ◽  
Standardized Precipitation Index ◽  
Meteorological Drought ◽  
Dry Season ◽  
Wet Season ◽  
Index Method ◽  
Spi Index ◽  
Maximum Duration ◽  
Relationship Of ◽  
The Relationship

Riau is one of the most vulnerable provinces to forest and land fires in Indonesia. The potency for forest and land fires is inseparable from the presence of peatlands and exacerbated by drought. The purpose of this research is to know the characteristics of meteorological drought using SPI (Standardized Precipitation Index) method and its relation with forest and peatland fire as one of disaster management effort in Riau Province. The data used in this research are monthly rainfall data from meteorology station and rainfall posts of BMKG, hotspot data from NOAA satellite, map of Forest Use Agreement (TGHK), peat land map and land use map. Analysis of drought characteristics was done by calculating monthly SPI-1 then determining the maximum duration, intensity, severity and drought exposure. Determination of the severity of the drought by weighting and suspension method was based on duration and intensity while drought exposure was done by overlaying the map of the severity of the drought with the land use map. Meanwhile, to know the potential of forest and land fires began with the selection of hotspots on peatlands and forest areas every month then created a graph of the relationship of meteorological drought with the number of hotspots. Then, to see the relationship of drought distribution to the distribution of hotspots in dry season (MK) and wet season (MH) of 2015 was done by overlaying cover the drought distribution with hotspot distribution. The result shows that drought characteristic in the most of Riau province has maximum duration around 4-6 months, dry category of intensity, high category of severity with exposure area in paddy field, field, habitation, and plantation. Then, negative SPI Index (dry condition) has potential to increase the number of hotspots otherwise positive SPI index (wet condition) leads to low occurrence of hotspot. The drought distribution in the dry season (July, August, September) of 2015 triggers the number of hotspots during drought conditions, while in wet season (April, November, December) of 2015 are dominated by normal conditions, some areas are dry and wet, resulting in lower hotspots distribution compared to the dry season.

The impacts of environmental and socioeconomic factors on the non-point source pollution in a small watershed in the Three Gorges Reservoir Area, China

2021 ◽  
Author(s):  
Jun Deng ◽  
Zhaoxia Li
Keyword(s):  
Land Use ◽  
Socioeconomic Factors ◽  
Fertilizer Application ◽  
Dry Season ◽  
Wet Season ◽  
Topographic Wetness Index ◽  
Wetness Index ◽  
Factors Affecting ◽  
Nps Pollution ◽  
Per Capita

<p>Determining the impacts of environmental and socioeconomic factors on nitrogen (N) and phosphorus (P) loss in the watershed is critical to reducing non-point source (NPS) pollution. This paper, we set 13 sampling points in the main stream and tributaries of watershed and sampled every two weeks from 2018 to 2020 to monitor the total nitrogen (TN) and total phosphorus (TP) concentration in the waterbodies. Twenty-six potential influencing factors affecting the nitrogen and phosphorus loss in the watershed were selected. The partial least squares regression (PLSR) was used to determine the relationship between TN and TP concentrations in the watershed and the 26 selected potential influencing factors. The results showed that the mean TN concentrations and mean TP concentrations in the dry season (11.42 mg·L<sup>−1</sup> and 0.09 mg·L<sup>−1</sup>, respectively) were both less than those in the wet season (13.20 mg·L−1 and 0.11mg·L−1, respectively). The optimal PLSR model explained 69.6%, 73.1% and 66.1% of the TN concentration variability, and 65.7%, 79.5% and 67.4% of the TP concentration variability during annual, dry season and wet season, respectively. According to the importance of the variables in the predicted value (VIP), topographic wetness index (TWI), planting structure (PS), interspersion and juxtaposition index (IJI), Orchard land use (OP), nitrogen fertilizer application (NF), per capita income (INCOME) and catchment area (AREA) were the key factors affecting TN concentration, whereas topographic wetness index (TWI), interspersion and juxtaposition index (IJI), population density (POP), slope gradient (SLOPE) and hypsometric integral (HI) were the key controlling factors of TP concentration. In addition, TN concentration was affected by cropland land use (CP) during the dry season and proportion of labor (LABOR) and per capita agricultural land area (ALA) during the wet season. TP concentration was affected by mean patch size (AREA_MN), phosphate fertilizer application (PF) and patch density (PD) during the dry season and residential area (RP) and values during the wet season. This study illustrates the impact of environmental and socioeconomic factors on NPS pollution, and can be used as a guide for effective NPS pollution control and water quality management.</p>

Temporal and spatial variation of fine roots in a northern Australian Eucalyptus tetrodonta savanna

2008 ◽  
Vol 24 (2) ◽  
pp. 177-188 ◽  
Author(s):  
David P. Janos ◽  
John Scott ◽  
David M. J. S. Bowman
Keyword(s):  
Fine Roots ◽  
Soil Surface ◽  
Dry Season ◽  
Annual Rainfall ◽  
Tropical Savannas ◽  
Wet Season ◽  
Temporal And Spatial Variation ◽  
Deep Roots ◽  
Temporal And Spatial ◽  
Peak Abundance

Abstract:Six rhizotrons in an Eucalyptus tetrodonta savanna revealed seasonal changes in the abundance of fine roots (≤ 5 mm diameter). Fine roots were almost completely absent from the upper 1 m of soil during the dry season, but proliferated after the onset of wet-season rains. At peak abundance of 3.9 kg m−2 soil surface, fine roots were distributed relatively uniformly throughout 1 m depth, in contrast with many tropical savannas and tropical dry forests in which fine roots are most abundant near the soil surface. After 98% of cumulative annual rainfall had been received, fine roots began to disappear rapidly, such that 76 d later, less than 5.8% of peak abundance remained. The scarcity of fine roots in the upper 1 m of soil early in the dry season suggests that evergreen trees may be able to extract water from below 1 m throughout the dry season. Persistent deep roots together with abundant fine roots in the upper 1 m of soil during the wet season constitute a ‘dual’ root system. Deep roots might buffer atmospheric CO2 against increase by sequestering carbon at depth in the soil.

scholarly journals Ecology, status and conservation of the Red-fronted Macaw Ara rubrogenys

1995 ◽  
Vol 5 (1) ◽  
pp. 61-78 ◽  
Author(s):  
Elin Pitter ◽  
Mette Bohn Christiansen
Keyword(s):  
Breeding Season ◽  
Arable Land ◽  
Rio Grande ◽  
Dry Season ◽  
Population Estimate ◽  
Wet Season ◽  
Drainage Systems ◽  
Local Farmers

SummaryA five-month study of the Red-fronted Macaw Ara rubrogenys, endemic to Bolivia, yielded a population estimate of 2,000–4,000 individuals. The species is resident and locally common in, but restricted to, an area in the drainage systems of the Rio Grande, Rio Mizque and northern Rio Pilcomayo. One-third of the population was composed of juveniles some three months after the end of the breeding season. During the dry season, with food apparently short, more of the day was spent feeding than during the wet season. Semi-deciduous vegetation along the rivers produced fruits and seeds that sustained the macaws during the dry season, but the conversion of such areas to arable land forces the macaw to depend for some months on crops and weeds. Local farmers consider the macaw a serious pest on maize.

scholarly journals Land use and landscape pattern impacts on water quality at multiple spatial scales in a subtropical large river

2021 ◽  
Author(s):  
Xiao Shu ◽  
Weibo Wang ◽  
Mingyong Zhu ◽  
Jilei Xu ◽  
Xiang Tan ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
River Water ◽  
Total Nitrogen ◽  
Landscape Pattern ◽  
Spatial Scales ◽  
Dry Season ◽  
Wet Season ◽  
Spatial And Temporal Scales ◽  
Multiple Spatial Scales

Abstract The coupling between land use/landscape pattern and water quality in river system varies across different spatial and temporal scales. It is important to understand the association between water quality and land use/landscape pattern across different spatial and temporal scales for the protection of water resources. Here, we measured seasonal water quality at 12 sub-basins in the upper reaches of the Han River (UHR) between 2010 and 2018. We conducted factor analysis and redundancy analysis to determine the links between land use and water quality at multiple spatial scales and to identify the main factors influencing water quality. We found that the concentration of nutrients, including total nitrogen, total phosphorus, nitrate-N, and ammonium-N were higher during the wet season than the dry season. Total nitrogen was identified as the main driver of nutrient pollution of UHR, whereas total phosphorus was identified as another potential nutrient pollutant. We also found that water quality parameters had a stronger related to land use types over the wet season than the dry season. Croplands and urban lands increased phosphorus concentrations of river water, whereas forest and grass lands decreased the nitrogen concentrations of river water at the sub-basins scale. Land use at riparian zone scales better explained variations in water quality than land use at sub-basin scales. The explained variations in landscape metrics were generally higher over the dry season compared to that over the wet season. The largest patch index and Shannon's diversity index were the main predictors of river water quality in UHR.

scholarly journals A Two-Stage Fuzzy Optimization Model for Urban Land Use: A Case Study of Chongzhou City

2021 ◽  
Vol 13 (24) ◽  
pp. 13961
Author(s):  
Jinjiang Yao ◽  
Bingkui Qiu ◽  
Min Zhou ◽  
Aiping Deng ◽  
Siqi Li
Keyword(s):  
Land Use ◽  
Arable Land ◽  
Optimal Solution ◽  
Urban Land ◽  
Urban Land Use ◽  
Western China ◽  
Cultivated Land ◽  
Construction Land ◽  
Land Use Structure ◽  
Urban Construction

Under the background of New-type Urbanization, with the continuous advancement of urbanization and the all-round development of cities, all kinds of demands are also rising. In the case of demand, it is difficult to quickly adjust from the land supply side and to guide the optimization of the structure and layout of land use is one of the methods to achieve this based on the current situation and shortage of urban land use structure and spatial arrangement. Because of the complexity, uncertainty and dynamics of the land use system, it is necessary to use an uncertain model to accurately describe and propose the approximate optimal solution, so this study analyzes the influencing mechanism of land use and optimize the land use structure under uncertainties by using a Bayesian network and fuzzy mathematical programming. Based on the results of the two stages of analysis, the cellular automata simulation is completed. The framework is applied to Chongzhou city in western China. The results indicated that the optimal land space for cultivated land is in the middle and the south based on the joint influence probability of arable land and urban construction land. The conversion probability of the area near the east is low, and the joint impact probability of construction land in all areas is generally similar except for the western protection area. After the optimization of the fuzzy planning, the optimal construction land scale is 69.42 km2. Under the condition that the cultivated land’s red line is guaranteed, there is still 98.87 km2 of space for the increase in cultivated land. It is found through simulation that the increase in construction land would occur in the central and western parts of Chongzhou, which may be caused by the urban siphon effect. According to Monte Carlo verification, when the conversion probability exceeds 50%, the cultivated land could be turned into urban construction land, with an accuracy of 91.99%. Therefore, this proposed framework is helpful to understand the process of land use and provides a reference for making scientific and reasonable territorial spatial planning and guiding land use practice under uncertainties.

The grazing habits of African-owned, East African zebu cattle in Zambia (Northern Rhodesia)

1965 ◽  
Vol 64 (3) ◽  
pp. 295-298
Author(s):  
C. A. Smith
Keyword(s):  
Land Use ◽  
Crop Residues ◽  
Arable Land ◽  
Dry Season ◽  
Zebu Cattle ◽  
East African ◽  
Eastern Province ◽  
Grazing Behaviour

The grazing behaviour of village cattle in the Eastern Province of Zambia (Northern Rhodesia) was studied.Usually, the cattle graze in the bush during the rains and on the dambos in the dry season. Where most of the upland was cultivated, the cattle were forced to graze in the dambos during the rains contrary to correct land use. The arable land and crop residues are grazed after the harvest in middry season.

Analyzing Land Use Impacts on Streamflow Response in a Tropical Watershed: A Hydrometric and Geochemical Approach

2020 ◽  
Author(s):  
Nicola Mathura ◽  
Kegan Farrick
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Critical Zone ◽  
Dry Season ◽  
Future Climate Change ◽  
Wet Season ◽  
Forested Catchment ◽  
Streamflow Response ◽  
The Caribbean ◽  
Geochemical Approach

<p>Climate change and unsustainable land use practices such as quarrying have the potential to negatively impact the hydrology and water resource availability in catchments. Throughout the Caribbean, hillside quarrying has become a common practice. While these activities remove large sections of the critical zone, very little work has been done on how hillside quarrying impacts storm response and catchment water storage.  The study is particularly important given the expected changes to rainfall patterns in the Caribbean under future climate change. We hypothesised that the removal of the critical zone during quarrying will increase the magnitude of streamflow response to storm events due to its close proximity to the river, while also reducing the overall storage of the watershed. This study utilized a hydrometric and geochemical approach with direct measurements of rainfall and streamflow, and bi-weekly water sample collections for geochemistry and <sup>18</sup>O and <sup>2</sup>H stable isotopes between the 3.6 km<sup>2</sup> Acono (forested) and the adjacent 3.6 km<sup>2</sup> Don Juan (quarried) watersheds, located in Trinidad and Tobago. A total of 1207 mm of rainfall occurred, with 87.3% falling from August to November (wet season) and 12.7% from December to March (dry season). The δ<sup> 18</sup>O in rainfall ranged from -7.7 to 0.3 ‰ across both seasons with an average δ<sup>18</sup>O of -3.5±1.8‰ during the wet season and 0.1±0.5‰ in the dry season. During the dry season the mean δ<sup> 18</sup>O of stream water showed a difference between the forested (-2.8±0.3‰) and quarried (-3.1±0.3‰) catchments whereas there was little differences in δ<sup>18</sup>O in the forested catchment (-3.3±0.3 ‰) and quarried catchment–(-3.2±0.27‰) in the wet season. Our stream δ<sup>18</sup>O dry season results suggests that different sources of water or anthropogenic influences such as water from settling ponds in the quarry could have impacted the δ<sup>18</sup>O of the quarried stream as we expected the forested catchment to be more stable. Sample collection at these sites is ongoing and additional parameters such as soil water isotopes and rainfall, soil and stream ion chemistry are expected to improve our understanding of the translation from rainfall to streamflow. This research will allow us to gain a better insight of the current hydrological processes within this catchment and aid in the long term adaptive planning for factors such as climate change and further land use change.</p><p> </p>

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