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<br />given location. Precipitation may be rain, snow, sleet, drizzle, freezing <br /> <br />rain, or all of them. River gages measure the height of the water surface <br /> <br />elevation in rivers or streams. Many types of river and rainfall gages are <br /> <br />available, depending on the degree of accuracy and sophistication required. <br />Although satellite and radar data are expensive, they can often be integrated <br />. I into a local flood warning system by using information available at the local <br />NWS office. In most instances, it is desirable to use some automated gages <br /> <br />with manual systems and some manual gages with automated systems. <br /> <br />C.l. Manual SY8te.s <br /> <br />. <br /> <br />The simplest and least expensive approach to data collection is to use <br /> <br />volunteer observers and inexpensive equipment to collect rainfall and river <br /> <br />level data. Inexpensive plastic rain gages can be used by volunteer observers <br />who report rainfall amounts by telephone to a community coordinator. Rainfall <br /> <br />reporting criteria can vary from reporting three times a day once a .5 inch <br /> <br />rainfall has been measured, to hourly if flood conditions are severe. River <br /> <br />stages are usually obtained by an observer who reads a simple staff gage or <br /> <br />wire weight gage and telephones the observations to a coordinator. <br /> <br />I . <br /> <br />C.2. Aut~ted Syst_ <br />A tipping bucket precipitation gage is used in most automated systems. The <br />tipping bucket, or event, gage is simple. Every time one millimeter of <br />rainfall fills the bucket, the bucket tips and causes a signal to be <br />transmitted to a radio transmitter unit. One tip of the bucket is frequently <br />called an event. The radio transmitter then instantaneously transmits a <br /> <br />unique station identifier and an accumulated precipitation value to a receiver <br /> <br />29 <br />