AREAS PRIORITARIAS, ESTRATEGIAS Y ACCIONES

The suitability of using hi storical data for this purpose is questionable where major chang- es are anticipated. Potable-water and nonpotable-water demands are specific to geograph- ic location, type of user, and many other factors. Water conservation plays an increasingly important role in total water-demand management and may result in a stabili zation or de- crease in average per capita potable-water use. However, the increase in available supply from water conservation is li mited, and a dual system can represent a long-term solution by delivering nonpotable water for appropriate uses.

For existing customers, the reclaimed-water market assessment should utilize po- table water consumption data from the utility providing potable water to customers in the study area defined for the project. Consumption data for several of the most recent years should be rev iewed to ensure that the data are not skewed ba sed on a particu larly wet or dry year. This is especial ly critical for irrigation applications. Also, reviewing sev- eral years of data enables the proper assessment of the stability of a potential customer’s potable-water usage. An average annua l potable-water consumption for each customer

can be developed, using the consumption data.

To calculate the estimated average nonpotable-water demand, the average annual potable-water consumption should be multiplied by the estimated percentage of potable-

water demand that can be supplied with reclaimed water. This percentage is based on the customer’s use of potable water. Data regarding the type of customer receiving the water can be obtained from the water utility, using the customer’s Standard Industrial Code (SIC) and land use zoning. For example, a golf course may be expected to use as much as 95 percent of its potable water for irrigation. This irrigation demand could be met with reclaimed water. Therefore, for planning purposes, 95 percent of the golf course’s existing average demand should be used for the reclaimed-water demand for a reclaimed- water project. Similarly, for a commercial user, it may be expected that 40 percent of the potable-water demand is used for irrigation and toilet water flush ing. Both of these uses

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36 PLANN ING FOR THE DISTRIBUT ION OF RECLAIMED WATER

are suitable for reclaimed water. Therefore, for planning purposes, 40 percent of the com- mercial user’s existing average demand could be used for the reclaimed-water demand for a reclai med-water project.

All potential users must be contacted to determine water quality and quantity re- quirements, operating requirements, delivery pressures, points of connection, and existing plumbing and facility layout. Severa l methods can be used to identify and survey potential reuse customers for the potential demand that may exist for reclaimed water. For estab- lished communities, an initia l step is to evaluate a community’s water meter sales records for potential reuse customers. Data from all large water meters (1 in. or 1 ½ in. and larger) should be compiled for both a dry and a wet year, and the data should be normalized to assess the impact of climate on the projected water use. If existing irrigation meters are installed, t he data should be segregated by potable-water meters and irrigation meters. In a recent planning study for Raleigh, N.C. (the capital of North Carolina with a population of 360,000 in 2007), the records indicated that there were almost 3,500 large water meters with an average daily demand of 24 mgd. Approximately 300 irr igation meters registered an average daily demand of 1 mgd or greater (Black & Veatch 2006).

Typically, the largest total water users and irrigation meter sales are identified and surveyed. The survey could consist of a simple questionnaire exploring what opportuni- ties the customer saw for using reclaimed water (see Table 3-1). Experience indicates that it is also useful to call 10 percent of the potential surveyed customers to collect more information after the sur vey is returned. A l isting of potential customers for each type of reclaimed-water use is developed, and telephone interviews conducted to as sess potential reuse demand. In areas where a number of golf courses serve the area residents, each should be contacted individually to encourage their use of reclai med water. The commu- nity should also examine its own potential for water reuse.

In new communities, or in areas of expansion in a community, existing customers do not exist, so it is necessary to use zoning maps a nd a community’s comp rehensive plan to make projections of future demand in the identified area(s). Such demand projections are obviously tied to land use, but they are also related to a community’s interest and adopted regulations regarding the required use of reclaimed water. If a community aggressively pushes the use of reclaimed water, their potential demand will be higher. Some commu-

nities may employ mandatory use ordinances to require reclaimed-water use in special cases.

City and county planning agencies typically have information regarding new devel- opment and redevelopment that are planned for their jurisdictions. Env ironmental docu- ments on file with local agencies are additional sources of information regarding future construction projects. Dual plumbing new construction projects for reclaimed-water use is much more cost-effective than retrofitting a site after constr uction has been completed . Therefore, future customers are typically excellent candidates for reclaimed-water use. By working with the developers of new construction and reconstruction projects in their plann ing stages, new customers can be cu ltivated at min imal cost, thereby increasing the

cost-effectiveness of the reclaimed-water project.

In summa ry, there are a variety of data that need to be considered.

The quality of the supply for the reclaimed water and the level of treatment

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that will be required to ensure that the quality of the reclaimed water will meet the users’ requirements.

The estimated percentage of each potential reclaimed-water customer’s ex-

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isting potable-water demand that could be met with reclaimed water. The estimated demand for reclaimed water from future customers resulting

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from redevelopment or new development.

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No reproduction or networking permitted without license from I HS

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PLANNING 37

The volume of reclaimed water available and its diurnal pattern, as well

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as the users’ diurnal usage patterns. The seasonal patterns of reclaimed- water supply and demand also should be reviewed. Information on both the diurnal and seasonal patterns will assist in determining the type of storage requirements that may be required for the project. This storage may occur at the utility’s facilities, at satellite storage facilities, or at specific customer locations.

All of these factors are considered by specific reclaimed-water use category as de- scribed in the following section.