**3. Monitoring water quality in urban Rivers**

Good quantification of urban impacts on rivers is needed to determine levels of degradation and begin the rehabilitation process. Depending on instrumentation, budgets and personnel; many water quality parameters are available with various uses toward the prediction of water quality (**Table 1**). Decisions on what to measure rests behind the objectives of the study and translation into effective policy for improvement.

Decision making begins with methodology and site selection gaining good access to a river for study. Barbour et al. [38] outlines several approaches. A targeted study where concerns over a specific outfall or disturbance entering the river may be one approach. Here, samples are taken above, in and below the concern. Comparisons are made to determine the extent of impact. Another approach is collection of information to assess the overall condition of the river and watershed. Sites are selected throughout the river basin then compared to a reference condition or norms of water health. In severely degraded urban areas historical data may be necessary for comparisons.

Concerning seasonality, samples should be taken during each significant season then characterized. Based on findings, an index time period is created to meet objectives. This allows the investigator to collect data during that time period and interpret findings within the bounds of the study. This approach is good for an overall analysis of urban river quality. If specific outfalls or problem areas are the concern seasonality may not need analysis.

Methodologies are dependent upon the parameter used. Water samples are measured using field instrumentation such as submersible meters and laboratory analysis detailed in publications such as Standard Methods [39]. Insects are collected using various types of nets, preserved and later sorted then enumerated. A rapid bioassessment (RBA) technique developed by Barbour et al. [38] is possible or if a more detailed approach is needed the use of bottom samplers such as a Surber or Hess is warranted. Comparisons between RBA and Surber methods have been studied [40]. For fish collections, electrofishing is the preferred collection technique [41]. It describes the pulsing of DC current into water temporarily immobilizing fish allowing collection for analysis.

Chemical water quality parameters are used individually or compiled into a metric dependent upon the investigator and the study. More data strengthens conclusions, however any data collection derived through a targeted study is beneficial. In 1970, a group of 142 water quality scientists developed a Water Quality Index (WQI) [42]. Using 9 prominent parameters (dissolved oxygen, fecal coliform/*E. coli*, pH, biochemical oxygen demand (BOD) (5-day), temperature change (from 1 mile upstream), total phosphate, nitrate, turbidity and total solids) the index was created for use in defining water quality. Multiple variations of the WQI have evolved (reviewed by Bharti and Katyal [43]) and are effective within defined use. Further, Noori et al. [44] explored the substitution of alternative measures into the


