Evaluation of the ecological status of an impaired watershed by using a multi-index approach

Abstract

The objective of this study was to use an integrative approach to assess the ecological status of a small river impacted by multiple sources of disturbance. The River Febros (NW Portugal) is a small and highly impacted non-regulated river; approximately 44% of the watershed area is dedicated to agriculture, but there is also some urbanization. Environmental status was evaluated using a new multi-index approach, combining quality indices for water (Water Quality Index (WQI)), benthic macroinvertebrates (Iberian Biological Monitoring Working Party Index (IBMWP)), and human modification (Riparian Forest Quality Index (QBR)); Ecological Status River Mediterranean Index (ECOSTRIMED); River Habitat Survey (RHS)). Surveys were car- four stretches of the main course of the river for physicochemical characteristics, as well as water microbiology and macroinvertebrates. Water quality was poor at all sites (WQI averaged 30.4%) and decreased downstream. The RHS (assessment of instream habitats and the river corridor) and the QBR quantification displayed the same trend. Macroinvertebrates diversity was permanently low with only the most tolerant insects taxa present; oligochaetes dominated. The ecological status of River Febros was well represented using the experimental assessment system, where a downstream decrease in condition was noticeable (in spite of a lower water quality upstream). Our results emphasize the importance of assessing several components of disturbed ecosystems in order to ascertain overall quality and the importance of promoting improvement of the riparian gallery as a buffer against multiple agents of disturbance.

Development of river water quality indices—a review

“…A few WQIs have also used modified additive methods that calculate the squared function of an aggregated index and then divide it by 100 (SRDD, 1976;Bordalo et al 2006;Carvalho et al 2011), as shown by the following equations: where the symbols in Equations (8) and (9) are the same as those in Equations (6) and (7). Bascarón (1979) proposed another modified version of the additive method for index aggregation, as shown in Equation (10).…”

“…Although no formal reports from environmental agencies were found regarding the application of these indices, there were some publications in the literature presenting the application of this WQI in the UK, where many reaches were evaluated using the general WQI (House 1990;Tyson and House 1989;House 1989;House and Ellis 1987). In addition, Carvalho et al (2011) adopted rating class of House Index when assessing water quality status of a small river in Portugal.…”

“…It is also called as the Scottish WQI. Although the SRDD index was originally developed for Scotland, it has later been modified and used to evaluate the status of water quality in several river basins from different countries (for example, Thailand (Bordalo et al 2001), Spain (Bordalo et al 2006), Portugal (Carvalho et al 2011) andIran (Dadolahi-Sohrab et al 2012)). The steps used for the application of SRDD index are as follows:…”

Penilaian Kerentanan Air Permukaan terhadap Pencemaran di Sub DAS Garang Hilir Berbasis Multi-Indeks

“…Hal tersebut mengakibatkan sungai lebih mudah dalam mengakumulasi berbagai jenis buangan dari daerah sekitarnya, sehingga menjadikan air sungai sangat rentan terhadap pencemaran yang banyak dipengaruhi oleh aktivitas manusia seperti pembuangan limbah industri (Azrina, Yap, Ismail, Ismail, & Tan, 2006;Mokaya, Mathooko, & Leichtfried, 2004), perkebunan, pertanian dan limbah perkotaan (Carpenter et al, 1998;Palmer, 1965), maupun proses alam seperti perubahan iklim, curah hujan dan transportasi sedimen (Ravichandran, 2003). Sungai yang tercemar mengakibatkan terjadinya degradasi pada kualitas air (Bordalo, Nilsumranchit, & Chalermwat, 2001;Carvalho, Cortes, & Bordalo, 2011), habitat fisik serta integritas biologi sistem lotik (sungai) (Carpenter et al, 1998;Varol & Şen, 2009) dan keanekaragaman hayati perairan (Maddock, 1999).…”

Influence of flow velocity, river size, a dam, and an urbanized area on biodiversity of lowland rivers

“…Disturbance of drainage basins includes various types of agriculture as well as areas impermeable to runoff, including urban areas. Thus, negative impacts of agriculture on aquatic species diversity was reported by Carvalho et al (2011), Opiso et al (2014), and Kim et al (2016); the influence of urban areas was characterized by Beixin et al (2012), Lakew & Moog (2015). Urban areas exert multiple pressures on river ecosystems, undermining their biodiversity (Rusanov & Khromov, 2016;Grizzetti et al, 2017;Kuzmanovic et al, 2017).…”