Water Quality of Drainage Canals and Assessment of Nutrient Loads Using QUAL2Kw

Abstract

The water quantity and quality in two of the four main drainage canals located in the plain of Chryssoupolis in Kavala, North Greece, are studied. The area is intensively used for agriculture. Irrigation water is supplied by Nestos River, using a network of irrigation canals. Drainage water and irrigation return flows are collected in the four main drainage canals, which outflow into the Thracian Sea, North Aegean. A monitoring program in the four canals was designed to monitor flow and main constituents of drainage water. Main pollutants included nitrate, phosphorus and suspended solids. Based on the collected data, the trophic state of the canals and its seasonal variation were assessed, and the limiting nutrient was identified. QUAL2Kw was also used to model flow and water quality in two of the four canals. The calibration and verification of QUAL2Kw was undertaken using the collected field data, in an effort to identify the pollution sources and propose future management actions for the improvement of drainage canal water quality. The results showed that QUAL2Kw is a useful tool to simulate water quality in rivers and canals, and to quantify the impacts of non-point source pollution from agricultural areas.

A simulation-based suitability index of the quality and quantity of agricultural drainage water for reuse in irrigation

“…Model predictions are acceptable for NOF values in the interval from 0.0 to 1.0 (Gikas, 2014). In Egypt, there are two main cropping seasons, summer and winter.…”

Use of Optimally Pruned Extreme Learning Machine (OP-ELM) in Forecasting Dissolved Oxygen Concentration (DO) Several Hours in Advance: a Case Study from the Klamath River, Oregon, USA

“…19) (ratio of standard deviation to RMSE), the scatter index (SI) (Eq. 20), also reported as the normalized objective function (NOF) (Gikas 2014), and the ratio of the mean absolute error to the standard deviation (RMAE) (Eq. 21).…”

“…A value of the RMAE less than 0.5 may be considered low, acceptable and appropriate for model evaluation (Singh et al 2004;Moriasi et al 2007). For the scatter index (SI), a perfect model has a SI equal to 0.0 (Gikas 2014), and for values between 0.0 and 1.0, the model predictions are acceptable (Boskidis et al 2010(Boskidis et al , 2011Gikas et al 2006;Pisinaras et al 2010).…”

“…DO is used to assess the trophic state of rivers, canals and lakes (Gikas 2014;Chamoglou et al 2014;Mellios et al 2015). During the last decade, much effort has been devoted to the modelling of DO in river, lake and stream ecosystems using artificial intelligence (AI) techniques, and much work has been done on this subject.…”

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“…At the same time, they are considered responsible for global environmental pollution to a great degree (Konstantinou et al 2006;Vryzas et al 2009;Vallée et al 2014). Runoff, leaching and groundwater drainage of agricultural fields are important forms of non-point source pollution, leading to degraded water quality in aquatic systems due to increased nutrient loads (Gikas et al 2014(Gikas et al , 2017 and pesticide entry (Vryzas et al 2012;Papadakis et al 2018). In addition, washing and filling of spray equipment, disposal of pesticide packages (empty containers), incorrect pesticide storage and accidents constitute other major forms of point source pollution (Vryzas et al 2012;Reichenberger et al 2007;Aktar et al 2009).…”