surface water - groundwater...
TRANSCRIPT
Surface Water - Groundwater Interaction:From Watershed Processes to Hyporheic Exchange
Donald O. Rosenberry, U.S. Geological SurveyMasaki Hayashi, University of Calgary, Canada
1
Groundwater Feeding Surface Water
Springs on river bank
GW-dependent ecosystem
Springs on river bankHeadwater spring
Winter et al. (1998. USGS Circ. 1139)
2
Groundwater-Surface Water Exchange by Bank Storage
3
Winter et al. (1998. http://pubs.usgs.gov/circ/circ1139/)
Bank Filtration Induced by Pumping
Thur River, Switzerland
Municipal water supplies use bank-filtrated groundwater.
4
http://www.cces.ethz.ch/projects/nature/Record/sites
“Hyporheic” Zone in the FloodplainActive Two-Way Exchange of Groundwater with River
5
Stanford (1998. Freshwater Biology, 40:402)
Hyporheic Exchange Mechanisms
Bedform-induced flow
5 cm
Pool-riffle sequence
50 m
Meandering channel
Hayashi and Rosenberry (2002. Ground Water, 40: 309)
10 m
pool
riffle
pool
Pool-riffle sequence
6
Riparian GW-SW interaction
0.14
0.15
Riparian plants start “pumping”
0.1
0.11
0.12
0.13
9/20 9/21 9/22 9/23 9/24 9/25 9/26 9/27
flo
w (
m3/s
)
Transpiration stops
7
Groundwater Flow System
Two fundamental rules that are generally true:1. Water table is a subdued replica of ground surface.2. Groundwater flows from high to low.
RechargeRecharge
8Marshak (2001. Earth: Portrait of a planet)
RechargeRecharge
Discharge
Groundwater is connected to streams
Water balance is key to understand the connection
= Storage Change− DischargeRecharge − Pumping
Long-term balance:
Recharge – Pumping ≈ Discharge
= Storage Change(water level ↑↓↑↓↑↓↑↓)
− DischargeRecharge − Pumping
Over pumping may cause:- Large drawdown of groundwater level- Reduction of flow, or drying of streams
9
Long-Term Effects of Groundwater Extraction
Example from Kansas, U.S.
Ogallala Aquifer
1961
Sophocleous (2000. J. Hydrol., 235: 27)
Major perennial streams in Kansas.
1994
10
200
300
Wate
r su
pp
ly (
10
6L
/d)
GW
SW
315××××106
Supplied by KUKL*
SW-GW Interaction in the Local Context
Population in Kathmandu Valley in 2011
Water Demand ~ 315××××106 L/day (135 L/person/day)
~ 2.3××××106
0
100
1 2 3 4 5 6 7 8 9 10 11 12
Wate
r su
pp
ly (
10
Month
*Kathmandu Upatyaka Khanepani Ltd.
Shrestha (2012. Kathmandu Valley Groundwater Outlook, Ch.10)
11
"Private" Water Supply to Cover Deficits
Is this viable?
Potential risks?
12
Shrestha et al. (2012. Kathmandu Valley Groundwater Outlook)
bedrockbedrock
lacustrine lacustrine
silty sandsilty sand
sandsandgravelgravelalluvial alluvial
fanfan
GeologyTopography
Kathmandu Valley
NENE
SWSW
bedrockbedrock
lacustrine lacustrine clayclaybedrockbedrock
< 1260 m1260-13601360-14601460-15601560-16601660-17601760-19601960-21602160-2360> 2360 m
Shrestha (2012. Kathmandu Valley Groundwater Outlook, Ch.3)
13
SWSW
shallow aquifershallow aquiferrecharge?recharge?
Conceptual Hydrostratigraphy
deep aquiferdeep aquifer
aquitardaquitard
bedrockbedrock
pressurepressure
14
recharge?recharge?
Shrestha (2012. Kathmandu Valley Groundwater Outlook, Ch.3)
How will an understanding of SW-GW interaction help us manage water resources sustainably?
stone spoutsbaseflow
dischargepumping
induced recharge
Pradhanang et al. (2012. Kathmandu Valley Groundwater Outlook, Ch.2)
15
waste dump polluted water
recharge