scholarly journals Watershed-level analysis of exceedance frequencies for different management strategies

2011 ◽  
Vol 46 (1) ◽  
pp. 64-73 ◽  
Author(s):  
Qi Yang ◽  
Glenn Benoy ◽  
Zhengyong Zhao ◽  
Thien Lien Chow ◽  
Charles P.-A. Bourque ◽  
...  

Exceedance of water-quality standards is important in assessing water quality. The effectiveness of soil conservation Beneficial Management Practices (BMPs) should be measured according to the BMPs' impact on exceedance frequencies. However, estimating exceedance frequencies for different management scenarios with field measurements is practically impossible due to difficulties in obtaining adequate data for analysing different combinations of BMPs. The objective of this modeling research was to analyse exceedance frequencies for different management strategies applied in the Black Brook Watershed (BBW). Daily concentrations of total suspended sediments (TSS) and soluble phosphorous (sol-P) were predicted with the Soil and Water Assessment Tool (SWAT) and assessed against water-quality standards from the Canadian Council of Ministers of the Environment (CCME) and National Agri-Environmental Standards Initiative-Ideal Performance Standards (NAESI-IPS). The investigated BMPs included conservation tillage, reduced fertilizer application, crop rotation, flow diversion terraces (FDT) and the combination of all four BMPs. The results indicated that FDT was the most effective at reducing exceedance frequencies of TSS and sol-P. Under the different management scenarios, we calculated the annual exceedance frequencies of TSS and sol-P concentrations above the CCME (20–45% and 10–26%) and NAESI-IPS (32–55% and 20–38%).

2007 ◽  
Vol 11 (6) ◽  
pp. 1785-1795 ◽  
Author(s):  
R. Quilbé ◽  
A. N. Rousseau

Abstract. Hydrological and pollutant fate models have long been developed for research purposes. Today, they find an application in integrated watershed management, as decision support systems (DSS). GIBSI is such a DSS designed to assist stakeholders in watershed management. It includes a watershed database coupled to a GIS and accessible through a user-friendly interface, as well as modelling tools that simulate, on a daily time step, hydrological processes such as evapotranspiration, runoff, soil erosion, agricultural pollutant transport and surface water quality. Therefore, GIBSI can be used to assess a priori the effect of management scenarios (reservoirs, land use, waste water effluents, diffuse sources of pollution that is agricultural pollution) on surface hydrology and water quality. For illustration purposes, this paper presents several management-oriented applications using GIBSI on the 6680 km2 Chaudière River watershed, located near Quebec City (Canada). They include impact assessments of: (i) municipal clean water program; (ii) agricultural nutrient management scenarios; (iii) past and future land use changes, as well as (iv) determination of achievable performance standards of pesticides management practices. Current and future developments of GIBSI are also presented as these will extend current uses of this tool and make it useable and applicable by stakeholders on other watersheds. Finally, the conclusion emphasizes some of the challenges that remain for a better use of DSS in integrated watershed management.


2014 ◽  
Vol 60 (4) ◽  
pp. 243-249 ◽  
Author(s):  
R.L. North ◽  
N.H. Khan ◽  
M. Ahsan ◽  
C. Prestie ◽  
D.R. Korber ◽  
...  

Lake Diefenbaker (LD) is a large reservoir on the South Saskatchewan River used for agricultural irrigation, drinking water, and recreation. Our objectives were to determine the distribution and abundance of bacterial indicators in embayments and the main channel of LD and to relate these to environmental factors. Total coliforms (TCs), fecal coliforms (FCs), and fecal indicator bacteria (i.e., Escherichia coli) were measured concurrently with water quality parameters. Although TCs, FCs, and E. coli were present in LD, they rarely exceeded the TC and FC Canadian Council of Ministers of the Environment (CCME) water quality standards for agricultural use (1000 colony-forming units (CFU) per 100 mL and 100 CFU per 100 mL, respectively). The correlation between the bacterial indicators in the sediments and the water column indicates that higher embayment abundances may be related to sediment loading and (or) resuspension events in these frequently mixed embayments. With higher water temperatures and water levels, as well as higher microbial activity, CCME bacterial limits may be exceeded. The greatest contributor to bacterial indicator abundance was water temperature. We predict that water quality standards will be exceeded more frequently with climate warming.


2014 ◽  
Vol 49 (4) ◽  
pp. 372-385
Author(s):  
Shawn Burdett ◽  
Michael Hulley ◽  
Andy Smith

A hydrologic and water quality model is sought to establish an approach to land management decisions for a Canadian Army training base. Training areas are subjected to high levels of persistent activity creating unique land cover and land-use disturbances. Deforestation, complex road networks, off-road manoeuvres, and vehicle stream crossings are among major anthropogenic activities observed to affect these landscapes. Expanding, preserving and improving the quality of these areas to host training activities for future generations is critical to maintain operational effectiveness. Inclusive to this objective is minimizing resultant environmental degradation, principally in the form of hydrologic fluctuations, excess erosion, and sedimentation of aquatic environments. Application of the Soil Water Assessment Tool (SWAT) was assessed for its ability to simulate hydrologic and water quality conditions observed in military landscapes at 5th Canadian Division Support Base (5 CDSB) Gagetown, New Brunswick. Despite some limitations, this model adequately simulated three partial years of daily watershed outflow (NSE = 0.47–0.79, R2 = 0.50–0.88) and adequately predicted suspended sediment yields during the observation periods (%d = 6–47%) for one highly disturbed sub-watershed in Gagetown. Further development of this model may help guide decisions to develop or decommission training areas, guide land management practices and prioritize select landscape mitigation efforts.


2009 ◽  
Vol 6 (3) ◽  
pp. 898-904
Author(s):  
D. Ilangeswaran ◽  
R. Kumar ◽  
D. Kannan

Various samples of groundwater were collected from different areas of Kandarvakottai and Karambakudi of Pudukkottai District, Tamilnadu and analyzed for their physicochemical characteristics. The results of this analysis were compared with the water quality standards of ISI, WHO and CPHEEO. In this analysis the various physicochemical parameters such as pH, electrical conductivity, turbidity, total dissolved solids, Cl-, F-, SO42-, PO43-, NO3-, NO2-, CN-, Nas+, K+, NH3, Mn, Fe, Ca & Mg hardnessetc., were determined using standard procedures. The quality of groundwater samples were discussed with respect to these parameters and thus an attempt were made to ascertain the quality of groundwater used for drinking and cooking purposes in and around Kandarvakottai and Karambakudi areas.


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