THE EFFECT OF LAVENDER MOUNTAIN ON RAINFALL DISTRIBUTION DUE TO OROGRAPHIC LIFTING

Rain shadow effects result when topographic barriers cause prevailing winds to lose moisture on the windward side, causing the leeward side to be without moisture. The purpose of this case study is to determine whether minimum relief (~275 m) in the Ridge and Valley Physiographic Region can influence rainfall distribution whereby the amount and pattern of localized rainfall has implications on watershed interactions, aquifer recharge, and storage capacity. This is important to local communities, agricultural operations, and other water based services (e.g. Rocky Mountain Reservoir Hydroelectric Facility). By using an array of 8 rain gauges spread across the ridge of Lavender mountain (four on the Northern slope and four on the Southern slope) we have been able to identify existing orographic effects on precipitation. During the summer season of 2017, May-September, 7 rainfall events (> 5 mm) were recorded. By adding the total rainfall from the gauges on the Northern slope and the gauges on the Southern slope and calculating the percent difference, three rainfall events produced differences in rainfall total across the ridge more than 5%; 5/28 (8%) 6/4 (13%) and 9/5 (21%). The windward slope for these events received the larger amount of precipitation, 5/28 produced 8% difference across the ridge with the southern slope being windward (WSW) and receiving the larger amount of rainfall. On 6/4 the rain event produced a 13% difference across the ridge with the southern slope being the windward (SSE) and receiving the larger amount of rainfall. On 9/5 the rain event produced a 21% difference across the ridge with the northern slope being both windward (NW) and receiving the larger amount of rainfall. By studying micro-climatic anomalies, better land and water use practices can be employed and predictions for severe weather conditions can be made more accurate on a local scale.