4/14 ERS 102 - -High precipitation and/or dam break •...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Geology 102 4/14/2008 Stream- Body of flowing water confined by a channel. (Variety of sizes and discharges): - Channel Bedrock Unconsolidated Drainage Basin = Watershed - Why care about Drainage Dividing: Heavily effect the discharge of the streams o Size of watershed o Character of watershed Floodplain- Flat area adjacent to a stream that is covered during floods. A floodplain size varies with gradient, discharge. - Floodplains tend to be in low radiant (low slope) with high discharge. Floods occur when stream overflows banks. Factors that influence discharge: - Runoff: Precipitation, snow melt (evaporation) - Infiltration: Transpiration (evaporation) Calculating Discharge: - Q (discharge)= Ac (cross section area) x V (velocity) - Q=Ac x V - Discharge- Amount of water flowing by a specific point in a fixed amount of time. Q= Ac x V - Stream Discharge= Area x Velocity Rating Curve correlates Stage Height to Discharge. Upstream Floods- Localized area, or small drainage basin
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: -High precipitation and/or dam break • Flash Floods: “upstream floods”-Small, localized area-High rainfall in short time period-Confined valleys-Move rapidly-Rare in Maine, but do occur (1981 Caribou, Me) • Riverine (Downstream) Floods:-Heavy rains over large area or rain combined with rapid snowmelt.-Riverine (a.k.a. floodplain) floods: o Floodplain: Broad, flat area, adjacent to stream • Floods in Maine:-“Seasonally pulsed”-Spring; High Precipitation and large snow pack & rapid melt-Fall: High Precipitation (hurricanes) and low transpiration • Ice Jam Floods:-Rapid snow melt + high precipitation-Sudden warming-Ice + high water-Saco River, 1936 • Flood Damage:-Erosion-Inundation-Interior Damage • How to predict Flood Hazards:-Monitoring of weather conditions-Precipitation- NWS-Snow Pack- MGS/USGS (Maine Geologic Survey/United States Geologic Survey)...
View Full Document

This note was uploaded on 04/18/2008 for the course ERS 102 taught by Professor Kelley during the Spring '08 term at University of Maine Orono .

Page1 / 2

4/14 ERS 102 - -High precipitation and/or dam break •...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online