8-13D-9-12: SURFACE WATER HYDROLOGY:

Source fluctuations, especially seasonally, have had an effect on the spatial variation in local hydraulic conditions along the major drainage and have an important role in determining the controlling processes involved with local flood processes, resulting flood features, and subsequent erosional attributes. In addition, ancestral hydraulic processes have contributed to a diverse depositional morphology, especially along Dry Creek.

The principal hydrologic feature in the study area is the Dry Creek drainage basin. The basin drains approximately sixty (60) square miles of intermountain uplands. Gauging station records from 1953 through 1968 show peak discharges range from three thousand five hundred (3,500) to four thousand seven hundred (4,700) acre- feet of water for the basin that includes the Hidden Springs project area. The peak flows appear to be concentrated from February through April. The exception is occasionally January shows moderately high flows.

Natural Springs: The diverse depositional environment associated with Dry Creek has contributed to unique conditions that promote artesian flow at a number of locations along Dry Creek within the Hidden Springs property boundary. Approximately nine (9) natural springs are clustered near the southeast corner of Section 31, the northwest corner of Section 5 and the southwest corner of Section 32, Township 5 North, Range 2 East.

Some diversion of spring flow has been attempted during the past for agricultural purposes, however, for the most part the springs have remained undeveloped. Flow of the springs is often intermittent and depends largely on seasonal precipitation and local water recharge. The most likely explanation for the springs and their historic characteristic is that they are fed by recharge from precipitation, upstream irrigation, and snowmelt from mountainous runoff generally from slopes to the north. Ancient streambeds (visible on current aerial photographs) probably transport the water from upstream surface and subsurface sources. The identification of shallow ground water areas is paramount in effective land use planning, especially during foundation engineering for residential development. The areas that have natural springs present are identified on the accompanying map. Some portions of these springs and the Dry Creek riparian area are wetlands areas.