scholarly journals The influences of the water diversion structure change on total phosphorus retention and implication for ecological flows in Yuqiao Reservoir, Tianjin

2020 ◽  
Vol 32 (2) ◽  
pp. 370-379 ◽  
Author(s):  
ZHANG Chen ◽  
◽  
SONG Didi ◽  
LIAN Tiehui ◽  
◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Structure Change ◽  
Water Diversion ◽  
Phosphorus Retention ◽  
Yuqiao Reservoir ◽  
Diversion Structure ◽  
Ecological Flows

A Phosphorus Budget for Lake Erie

1976 ◽  
Vol 33 (3) ◽  
pp. 564-573 ◽  
Author(s):  
N. M. Burns ◽  
J. D. H. Williams ◽  
J.-M. Jaquet ◽  
A. L. W. Kemp ◽  
D. C. L. Lam
Keyword(s):  
Total Phosphorus ◽  
Lake Erie ◽  
Central Basin ◽  
Phosphorus Retention ◽  
Western Basin ◽  
Eastern Basin ◽  
Phosphorus Budget ◽  
Natural Origin ◽  
Lake Bottom ◽  
Entire Lake

A budget for phosphorus retention in Lake Erie during 1970 has been drawn up. Phosphorus associated with sand-sized particles (> 63 μm) was excluded. Retention of apatite phosphorus (AP) and nonapatite phosphorus (NAP) within each of the three basins of the lake (Western, Central, and Eastern) was estimated in each case by two independent methods. The two estimates of retention of total phosphorus within the entire lake agreed to within 9.5% of their mean. The estimates of AP retention within the Western basin also agreed well. However, the input–output balance estimates of AP retention in the Central basin and of NAP retention in the Western and Central basins greatly exceeded the corresponding sedimentation values, while in the Eastern basin this pattern was reversed. The AP discrepancy was attributed to unobserved transport of AP from the Central to the Eastern basin via nearshore currents past Long Point, while the NAP discrepancies were largely attributed to eastward movement of NAP through the lake within about 2 m of the lake bottom. The total amount of phosphorus retained within the lake in 1970 was 41,000 metric tons, or about 92% of input. AP of natural origin and inert nature accounted for approximately 44% of the total phosphorus retained. A reduction in anthropogenic phosphorus input of about 15,000 metric tons/yr, as called for in the Great Lakes Water Quality Agreement, will reduce present annual NAP loading to close to pre-1850 values.

Carbon dynamics of pristine and hydrologically modified fens in the southern Rocky Mountains

2003 ◽  
Vol 81 (5) ◽  
pp. 477-491 ◽  
Author(s):  
Rodney A Chimner ◽  
David J Cooper
Keyword(s):  
Water Table ◽  
Rocky Mountains ◽  
National Park ◽  
Net Primary Production ◽  
Rocky Mountain ◽  
Rocky Mountain National Park ◽  
Plant Production ◽  
Water Diversion ◽  
Southern Rocky Mountains ◽  
Diversion Structure

We measured water table levels, above- and below-ground plant production, and CO2 and CH4 emissions for five fens in Rocky Mountain National Park, Colorado, to determine whether a water diversion project was adversely affecting carbon cycling. Two fens were located beneath the water diversion, and three fens were located in an adjacent pristine watershed. The diversion lowered water table levels in one fen, while the other fen was not hydrologically modified. Total NPP (net primary production) for all sites ranged from 130 to 316 g C·m–2·year–1, with a mean of 217 g C·m–2·year–1, and belowground NPP accounted for ~60% of the total. Maximum CO2 emissions for pristine fens ranged between 170 and 273 mg CO2-C·m–2·h–1, with annual emissions of 230–388 g CO2-C·m–2·year–1. However, the hydrologically modified fen had maximum CO2 emissions of 457 mg CO2-C·m–2·h–1 and had an annual flux of 573 g CO2-C·m–2·year–1. Maximum CH4 emissions ranged from 3 to 25 mg CH4-C·m–2·h–1, with annual emissions of 9–61 g CH4-C·m–2·year–1. The water diversion structure lowered water tables, increased CO2, decreased CH4 and NPP, and resulted in the site likely becoming a net source of carbon.Key words: peatlands, fens, CO2, CH4, hydrology, Rocky Mountains, Rocky Mountain National Park, plant production.

scholarly journals Recovery of Forest Soil Chemical Properties Following Soil Rehabilitation Treatments

2019 ◽  
Vol 41 (1) ◽  
pp. 163-175 ◽  
Author(s):  
Megdad Jourgholami ◽  
Somayeh Khajavi ◽  
Eric R. Labelle
Keyword(s):  
Soil Properties ◽  
Chemical Properties ◽  
Control Area ◽  
Soil Chemical Properties ◽  
Water Diversion ◽  
Available P ◽  
Total N ◽  
Organic C ◽  
Available Nutrients ◽  
Diversion Structure

Several rehabilitation treatments have been applied to mitigate runoff and sediment in machine trafficked areas following logging operations, while the knowledge on the consequence of these remediation techniques on the recovery of soil properties remains scarce. The objective of the study was to determine the effect of different rehabilitation treatments including sawdust mulch (SM), water diversion structure (WDS), untreated/bare trail (U), and undisturbed or control area (UND) on the recovery of soil chemical properties over a six-year period after machine-induced compaction occurred on three longitudinal trail gradients (10, 20, and 30 %).In each treatment, the following soil properties were measured: litter thickness, pH, EC, soil organic C, total N, and available P, K, Ca, and Mg. Five sampling plots (with 10 m length and 4 m width) were positioned in each trail gradient classes and three of these plots were randomly considered for soil sampling.The results demonstrate that litter thickness differed among the three treatments, with the highest amount present on the UND area and lowest on the U treatment. Meanwhile, the highest pH (6.75), EC (0.21 Ds m−1), N (0.27 %), available P (14.61 mg kg−1), available K (123.5 mg kg−1), available Ca (135.1 mg kg−1), and available Mg (42.1 mg kg−1) and the lowest C (1.21 %) and C/N ratio (7.83 %) were found on the SM with gradient of 10 % compared to other gradient classes on SM, WDS and, U treatments. The recovery value of litter depth, pH, EC, C, N, C/N ratio, and available nutrients (P, K, Ca, and Mg) were higher on the SM than the WDS at the gradient of 10 %, while significantly higher levels of these variables were measured under WDS installed on trail gradients of 30 % and 20 % when compared with the same gradients on SM. Results of the study revealed that soil chemical properties showed some evidence of recovery following SM and WDS rehabilitation treatments compared to U, although these properties did not fully recover within 6 years as compared to UND area.

scholarly journals Reservoir Operation Policy based on Joint Hedging Rules

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 419 ◽  
Author(s):  
Baohui Men ◽  
Zhijian Wu ◽  
Yangsong Li ◽  
Huanlong Liu
Keyword(s):  
High Reliability ◽  
Water Shortage ◽  
Water Diversion ◽  
Control Groups ◽  
Hedging Rule ◽  
Standard Operation ◽  
Yuqiao Reservoir ◽  
Transfer Cost ◽  
Supply Capacity ◽  
Better Than

When the water supply capacity of the reservoir is small, hedge rule (HR) can be applied to reduce the risk of unacceptably large damage from water shortage during drought. Moreover, in water-receiving areas of water diversion project, it is important to reduce transfer based on HR when the water-receiving area is in a wet period so as to reduce the water transfer cost. This paper improved the traditional HR and proposed a new kind of hedging rule named joint hedging rule (JHR). JHR was applied to Yuqiao Reservoir of Tianjin in China and was compared with HR and standard operation policy (SOP) as two control groups. The result indicates that JHR performs better than HR and SOP, which cannot only mitigate the risk of unacceptably large damage from water shortage by one hedge process but also reduce the transferred water by another hedge process. In addition, the number of days of different water shortage, the storage ratio at the end of the year, and transferred water result indicates that JHR is of high reliability and practicability.

scholarly journals Modeling nutrient in-stream processes at the watershed scale using Nutrient Spiralling metrics

2009 ◽  
Vol 13 (7) ◽  
pp. 953-967 ◽  
Author(s):  
R. Marcé ◽  
J. Armengol
Keyword(s):  
Total Phosphorus ◽  
Phosphorus Concentration ◽  
Phosphorus Retention ◽  
Fine Scale ◽  
Watershed Scale ◽  
Efficiency Loss ◽  
Biogeochemical Models ◽  
Global Patterns ◽  
Nutrient Spiralling

Abstract. One of the fundamental problems of using large-scale biogeochemical models is the uncertainty involved in aggregating the components of fine-scale deterministic models in watershed applications, and in extrapolating the results of field-scale measurements to larger spatial scales. Although spatial or temporal lumping may reduce the problem, information obtained during fine-scale research may not apply to lumped categories. Thus, the use of knowledge gained through fine-scale studies to predict coarse-scale phenomena is not straightforward. In this study, we used the nutrient uptake metrics defined in the Nutrient Spiralling concept to formulate the equations governing total phosphorus in-stream fate in a deterministic, watershed-scale biogeochemical model. Once the model was calibrated, fitted phosphorus retention metrics where put in context of global patterns of phosphorus retention variability. For this purpose, we calculated power regressions between phosphorus retention metrics, streamflow, and phosphorus concentration in water using published data from 66 streams worldwide, including both pristine and nutrient enriched streams. Performance of the calibrated model confirmed that the Nutrient Spiralling formulation is a convenient simplification of the biogeochemical transformations involved in total phosphorus in-stream fate. Thus, this approach may be helpful even for customary deterministic applications working at short time steps. The calibrated phosphorus retention metrics were comparable to field estimates from the study watershed, and showed high coherence with global patterns of retention metrics from streams of the world. In this sense, the fitted phosphorus retention metrics were similar to field values measured in other nutrient enriched streams. Analysis of the bibliographical data supports the view that nutrient enriched streams have lower phosphorus retention efficiency than pristine streams, and that this efficiency loss is maintained in a wide discharge range. This implies that both small and larger streams may be impacted by human activities in terms of nutrient retention capacity, suggesting that larger rivers located in human populated areas can exert considerable influence on phosphorus exports from watersheds. The role of biological activity in this efficiency loss showed by nutrient enriched streams remained uncertain, because the phosphorus mass transfer coefficient did not show consistent relationships with streamflow and phosphorus concentration in water. The heterogeneity of the compiled data and the possible role of additional inorganic processes on phosphorus in-stream dynamics may explain this. We suggest that more research on phosphorus dynamics at the reach scale is needed, specially in large, human impacted watercourses.

scholarly journals Simulation of the Parameters Effecting the Water Quality Evolution of Xuanwu Lake, China

2021 ◽  
Vol 18 (11) ◽  
pp. 5757
Author(s):  
Min Pang ◽  
Weiwei Song ◽  
Yuan Liu ◽  
Yong Pang
Keyword(s):  
Water Quality ◽  
Diffusion Coefficient ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Water Environment ◽  
Water Diversion ◽  
Nitrogen Concentrations ◽  
Implementation Effect ◽  
Degradation Coefficient

After years of water environment improvement, China’s water quality has improved to some extent in recent years. However, different water areas have different characteristics of water pollution. The paper used mathematical models to investigate the influence of different parameters on the water quality of Xuanwu Lake, China. The predominant focus was on the nutrients concentration due to changing the amount of pollutants, degradation coefficient, water diversion discharge and diffusion coefficient. The results showed that the amount of pollutants had the most significant impact, followed by the degradation coefficient. The total phosphorus and total nitrogen concentrations of Xuanwu Lake increased with the increase of the amount of pollutants. The water quality of Xuanwu Lake decreased significantly with the increase of degradation coefficient. Increasing the water diversion discharge will not only make a big difference in water quality, but it will also worsen the water quality. The effect of the amount of pollutants on Xuanwu Lake total phosphorus and total nitrogen is 4.1 and 5.7 times that of water diversion discharge. The influence of total phosphorus and total nitrogen in the degradation coefficient scheme is 3.5 and 6.2 times that of the water diversion discharge scheme. The diffusion coefficient has almost no effect on the water quality of Xuanwu Lake. From the practical difficulty and implementation effect of water environment improvement, the order of water quality improvement effect from good to bad is as follows: the amount of pollutants scheme, degradation coefficient scheme, water diversion scheme, diffusion coefficient scheme. Under the circumstance of limited water diversion, the lake will effectively improve the water quality. Reducing the discharge of pollutants is the fundamental measure to control water environment problems, and water diversion is an auxiliary measure to improve the water ecology. It will become a trend to combine the reduction of pollutant discharge and water transfer for water environment improvement. This paper is of significance for improving the water quality of Xuanwu Lake, and it also provides a scientific method for water environment improvement of water diversion projects.

Phosphorus inactivation by aluminum in Lakes Gårdsjön and Härsvatten sediment during the industrial acidification period in Sweden

2005 ◽  
Vol 62 (8) ◽  
pp. 1702-1709 ◽  
Author(s):  
Brian J Huser ◽  
Emil Rydin
Keyword(s):  
Nutrient Cycling ◽  
Acid Deposition ◽  
Total Phosphorus ◽  
Lake Acidification ◽  
Phosphorus Retention ◽  
Substantial Portion ◽  
Sediment Phosphorus ◽  
Phosphorus Inactivation ◽  
P Retention ◽  
P Cycle

Acidification of lakes exposed to acid deposition is generally accompanied by a severe decrease in production (oligotrophication). In this study, we examined sediment from Lakes Gårdsjön and Härsvatten, Sweden, to determine whether sediment phosphorus (P) retention increased during the years corresponding to lake acidification. Sediment from both lakes had increases in aluminum (Al) in the upper 10 cm, and dating of Lake Gårdsjön sediment revealed that the Al increase occurred from 1950 to 2001 in this lake. The increase in Al input caused an increase in Al-bound P (Al–P) formation and overall sediment total phosphorus retention during the same period. Lake Gårdsjön received an additional 12.9 g·m–2 of Al, above preacidification background levels, that bound 1.1 g·m–2 of P and removed it from the in-lake P cycle from 1950 to 2001. A substantial portion (up to 76%) of the total external P load eventually was converted to Al–P and buried in the sediment over this period. The increase in sediment P burial due to increased formation of Al–P in systems similar to Lake Gårdsjön may have detrimental effects on nutrient cycling, and as a result, on productivity within the lake, leading to acido-oligotrophication.

scholarly journals Eutrophication forecasting and management by artificial neural network: a case study at Yuqiao Reservoir in North China

2015 ◽  
Vol 17 (4) ◽  
pp. 679-695 ◽  
Author(s):  
Ya Zhang ◽  
Jinhui Jeanne Huang ◽  
Liang Chen ◽  
Lan Qi
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Water Temperature ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Ann Model ◽  
Validation Data ◽  
Yuqiao Reservoir ◽  
Artificial Neural ◽  
Sound Management

Yuqiao Reservoir is the potable water supply source for a city with a population of more than 14 million. Eutrophication has threatened the reliability of drinking water supplies and, therefore, the forecasting systems for eutrophication and sound management become urgent needs. Water temperature and total phosphorus have long been considered as the major influencing factors to eutrophication. This study used the artificial neural network (ANN) model to forecast three water quality variables including water temperature, total phosphorus, and chlorophyll-a in Yuqiao Reservoir. Two weeks in advance for forecasting was chosen to ensure a sufficient preparation response time for algae outbreak. The Nash–Sutcliffe coefficient of efficiency (R2) was between 0.84 and 0.99 for the training and over-fitting test data sets, while it was between 0.59 and 0.99 for the validation data set. To better respond to the algae outbreak, a number of management scenarios formed by orthogonal experimental design were modeled to assess the responses of chlorophyll-a and an optimal management scenario was identified, which can reduce chlorophyll-a by 23.8%. This study demonstrates that ANN model is potentially useful for forecasting eutrophication up to 2 weeks in advance. It also provides valuable information for the sound management of nutrient loads to reservoirs.

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