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D. Selection of Landscapes Suitable for Irrigation with Recycled Water- <br /> Presentation by Nelda Matheny, President, HortScience, Inc.; <br /> <br /> Nelda Matheny stated that she was asked to speak on this issue tonight because <br /> she is unable to attend the meeting on September 16. She stated that recycled <br /> water for landscapes has been used for decades and California there are <br /> hundreds of communities that use recycled water. She stated that there are <br /> significant issues to be concerned with when changing from a potable water <br /> source to a recycled water source on existing landscape. The four issues are <br /> water quality, plant tolerances and requirements, the type of irrigation present, and <br /> the site conditions (primarily soil). <br /> <br /> Water Quality: The quality of the water coming out of the recycled units depends <br /> upon the potable water coming out of the tap. The water then acquires some <br /> components, which is called wastewater; the wastewater then goes into a sedous <br /> of treatments with the quality of water coming out dependent upon what the <br /> treatments consist of. Based on the proposed project, the recycled water will have <br /> advanced treatments and actually meets the requirements for consumption, <br /> although consumption is not planned. <br /> <br /> Plant Tolerances and Requirements: <br /> The salts accumulate in the soil after each watering. Plant requirements are <br /> different than those for human consumption and different cdteria must be used for <br /> interpreting the analysis. The quality of the water cannot be based solely on <br /> human tolerance, but from a plant tolerance aspect. Tap contains salts and <br /> recycled water contains more salt and chloride ions. The analysis shows in <br /> regards to the total salts, the level of 1,500 is a potentially moderate problem. The <br /> chloride if sprayed on foliage is more of an issue than if applied to the soil and the <br /> same applies for the sodium. Boron will not be an issue faced with this recycled <br /> water. Plants vary dramatically in their tolerance to salts so in order to evaluate <br /> them, it must be determined which species are present. <br /> <br /> Irriqation: <br /> If irrigation occurs primarily by sprinkler the concern would be the amount of <br /> chloride and sodium that will be absorbed through the foliage. Another issue is <br /> how frequently water is applied because every time water is received, more salts <br /> are absorbed. <br /> <br /> Soil: <br /> There are three elements to consider: texture, whether sandy or clay; chemical <br /> characteristics, such as a lot of salt already present; and the drainage. Over time <br /> as water with salts is applied, the salts accumulate in the upper levels of the soil <br /> and we rely on rainfall to push those salts below the roots in wintertime. If there is <br /> something prohibiting the water from going downward, the leeching effect does <br /> not occur. Pt is extremely important that there be adequate drainage in the soil <br /> being irrigated with recycled water. <br /> <br />REGULAR COUNCIL MEETING AUGUST 26, 2002 <br />MINUTES PAGE 8 <br /> <br /> <br />