lummi island water resources · 2017. 6. 15. · powerpoint presentation author: robert mitchell...
TRANSCRIPT
Lummi Island Water Resources
Bob Mitchell
May 25, 1999 “A Fresh Look at Groundwater on Lummi Island”
Photo by Al Marshal
Hydrology is the science that examines the occurrence and movement of atmospheric, surface, and groundwater
http://rdnwaterbudget.ca/water-101/aquifers-groundwater/
Groundwater occurs in the void spaces of sediments or in the fractures in rocks
An aquifer is a geologic formation that can store and transmit water at rates fast enough to supply reasonable amounts to wells.
Domestic well – 10s of gallons per minute
Irrigation well – 100s of gallons per minute
Municipal well – 1000s of gallons per minute
Lummi Island Lidar Lummi Island Relief
Lummi Island Geology
Emergent Beach Deposits
Emergent Beach Deposits
Chuckanut Formation
Glaciomarine Drift
https://fortress.wa.gov/ecy/waterresources/map/WCLSWebMap/
Chuckanut Formation Fine Grained SedimentsCoarse Grained Sediments
100 ft
Aquifer Recharge is controlled by a variety of factors: ∆
GROUND WATER
SOIL WATER
1. Precipitation variability in space and time (duration, intensity, and magnitudes)
2. Soil type and surficial geology (controls infiltration rates and water storage)
3. Topographic relief (controls precipitation runoff)
4. Degree of evapotranspiration (controls soil-water loss)
Recharge = precipitation – runoff - evapotranspiration – soil storage
.
http://www.prism.oregonstate.edu/
30-year average rainfall (PRISM)
Each PRISM grid cell is ~ 0.55 km2 (or 0.21 square miles)
Lummi Island Rainfall
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http://www.prism.oregonstate.edu/
Each PRISM grid cell is ~ 0.55 km2 (or 0.21 square miles)
Lummi Island Rainfall
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Rain
fall
(inch
es)
Bellingham 3 SSW, WA1981-2010 Monthly Normals
050
100150200250300350400450500
0.01
0.04
0.07 0.
1
0.13
0.16
0.19
0.22
0.25
0.28
0.31
0.34
0.37 0.
4
0.43
0.46
Freq
uenc
y
Hourly Rainfall (inches)
Due to our maritime climate, rainfall intensities are low in the Puget Sound region
Weather Station in the Lake Whatcom Watershed
Infiltration (and runoff) is controlled by soil type, thickness, original water content, and precipitation characteristics
light rain – more infiltration heavy rain – more runoff
infiltration
runoff
Vegetation intercepts and stores precipitation that eventually evaporates
interception/storage
Vegetation removes water from soils and transpires (evaporates) it to the atmosphere
stomata
6CO2 + 6H2O → C6H12O6 + 6O2
light
plant matter
Photosynthesis
Evapotranspiration (ET) is a term used to quantify all evaporative losses in a watershed
1) Evaporation of water intercepted and stored by vegetation
2) Water transpired by vegetation
3) Water evaporated from soil
ET accounts for about 60 to 70% of the water loss from a slope
lowers water content in soil
evaporation of water stored by interceptiontranspired water
evaporation of soil water
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Inch
es o
f Wat
er
Rainfall
Evapotranspiration
Rainfall inputs and evapotranspiration outputs
Recharge Estimates – Aspect Consulting
https://pubs.usgs.gov/fs/2000/fs-057-00/pdf/fs05700.pdf
Seawater Intrusion
Seawater Intrusion
Arsenic Distributions
Source: Oriana Chegwidden at UW Computational Hydrology lab
Climate change predictions by global climate models
Climate Forecasts
CMIP5 – Coupled Model Intercomparison Project Phase 5, March 2013 includes 20 Climate Modeling groups from around the world.
GCM – global climate model
RCP – Representative Concentration Pathways (future greenhouse gas emission narrative )• RCP 4.5 – moderate emission narrative • RCP 8.5 – severe emission narrative
From Knutti and Sedlacek, 2013
http://maca.northwestknowledge.net/tool_scatterplot.php
GCMS with RCP 4.5; 2040-2069 GCMS with RCP 8.5; 2040-2069
http://maca.northwestknowledge.net/tool_scatterplot.php
GCMS with RCP 4.5; 2070-2099 GCMS with RCP 8.5; 2070-2099