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Guadalupe River Small Guadalupe River Small Tributaries Loading Study: Tributaries Loading Study:
Do we continue?Do we continue?If so How!!If so How!!
Lester McKeeLester McKeeSan Francisco Estuary Institute, Oakland, CA
San Francisco Estuary Institute
Item #3b
Sediment Load Variability in the Bay Area
y = 4.8675x1.3789
R2 = 0.904
1
10
100
1000
10000
100000
1 10 100 1000
Flow variability (Dimensionless)
Se
dim
en
t lo
ad
va
ria
bili
ty (
Dim
en
sio
nle
ss)
Sediment Load Variability in the Bay Area
y = 4.8675x1.3789
R2 = 0.904
1
10
100
1000
10000
100000
1 10 100 1000
Flow variability (Dimensionless)
Se
dim
en
t lo
ad
va
ria
bili
ty (
Dim
en
sio
nle
ss)
Guadalupe sediment load variationpredicted to be 2,300x
Rainfall Intensity Hypothesis
Hg (mg/kg)
Measured Hg Loads Variation
0
20
40
60
80
100
120
140
160
2003 2004 2005
Water Year
To
tal M
ercu
ry (
kg)
Estimated Hg Load Variability
0.01
0.1
1
10
100
1000
10000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Years of Averaging
Min
imu
m a
nd
Ma
xim
um
Lo
ad
(kg
)
Options for Continuation(see word document for details)
• Option 1: Discontinue– $0k
• Option 2: Continue Status Quo– $80k per year (local sponsor) + $50k per year (RMP) = $130k/y
• Option 3: Large Floods Only – Falling Stage– $35k per year (USGS) (every year ongoing)– $15k (SFEI labor) + $10k (Hg lab analysis) only when a large
flood occurs = $25k– $140k full study every 5 years (next time would be in water year
2011)
