The planet Earth is inherently short of freshwater, the proportion of which  is as little as 3 percent of all available water.  The remaining

97   percent of water is  saline  and  is stored  in  the  oceans.  Of the 3

percent of water that is freshwater, only 0.3 percent flows through surface water systems such as rivers and lakes; the remaining 2.97 percent is frozen in glaciers and ice caps or held in the ground.

This inherent scarcity has been worsened by the accelerated diversion of water for agricultural, commercial, industrial, and residential uses, which has increased greatly in response to a growing world population that reached 6.5 billion people in 2006. As agriculture increasingly is becoming dependent on irrigation the most populous continent, the availability of water for industrial, commercial, and municipal uses has been shrinking.

The process of designing a water resources monitoring program begins with a clear definition of program goals and objectives.  

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Ideally, the data obtained through monitoring provide an objective source of information needed to support management decisions. Specifically, an effective water-quality monitoring program will provide quantitative answers to the following questions: 1) what is the condition of the source water? 2) Where, how, and why are water-quality conditions changing over time? 3) What problems are related to source-water quality? Where are the problems occurring and what is causing them? 4) Are programs to prevent or remediate problems working effectively? 5) Are water-quality goals and standards being met?

Specific objectives of the program are to:

     • Monitor the condition of source waters in the Nation drinking water supply system;

     • Determine where, when, and how water-quality conditions are changing over time;

     • Identify actual and potential problems related to source-water quality;

     • Evaluate effectiveness of programs to prevent or remediate problems;

     • Ensure that all applicable water-quality goals, standards, and guidelines are being met;

     • Provide for rapid response to emerging problems.

     Water    entering   the  reservoirs is  monitored  at  primary  and

secondary tributary-stream-monitoring stations. These stations represent streams that contribute water directly to the reservoirs and major tributaries, or integrate large areas of the drainage basin. Thus, the stations are important primary indicators of the condition of water likely to enter the reservoirs.

     Specific conductance, pH, water temperature, turbidity, and dissolved oxygen concentration are measured on site and water samples are collected in accordance with clean-sampling protocols into 1-liter Teflon isokinetic samplers. Discharge-weighted, representative samples are collected from multiple vertical profiles distributed at equal distances along stream cross sections. The samples are then returned to the laboratory for analysis of color, fecal coliform bacteria, alkalinity, total suspended solids, and concentrations of major ions, nutrients, and selected metals. 

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     The secondary stream-monitoring stations are monitored twice a year, usually during base flow and high flow. These stations are located higher up in the drainage basin on smaller tributaries or at points that discharge to the reservoirs predominantly during wet weather. The secondary stations are sampled biannually for the same constituents as the primary stations to provide indicators of potential changes in water quality or of base-flow conditions.

     Monitoring of water resources includes the investigation of specific point-source locations that contribute contaminants to the water supply. These locations are not tributary sampling stations, rather outfalls, or elicit discharges that enter tributaries, whose sources were detected by routine or stormwater sampling in the tributaries and traced back upstream to their specific location.

    The special investigations of water-quality-related problems and situations within the source area may include intensive monitoring at present water-quality-monitoring stations where increasing trends in contaminant loading have been noted, monitoring at locations where a known disturbance is taking place, and monitoring to assess the effectiveness of new management practices or infrastructure. These investigations frequently require analysis of a variety of constituents and water- quality related properties.

Exercises