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Adapting Water Allocation Systems: Challenges and Opportunities
The Upper Guadiana and Llobregat Delta cases.
Jesus CarreraGHS UPC-CSIC
IDAEA, CSIC
April, 25th, 2019Adapting Water Rights to Face Climate Change Impacts: A Comparison of California
and SpainThe Botin Foundation and Rosenberg International Forum on Water Policy
Consejo Superior de Investigaciones Científicas
I am going to:
• Briefly summarize the main challenges, and why I am discussing the two cases I will be discussing
• Addressing climate change at the UpperGuadiana Basin
• Addressing seawater intrusion at the Llobregat Delta Aquifer
Rainfall patterns of Spain similar to thoseof California
Guadiana River, now…
… and before
And we face similar challenges:1) water over use (and loss of base flow)
After pumping starts, the river flow rate decreases progressively (by the same amount but with 10 y delay)
(MIMAM, 2000; Custodio, 2017).
And we face similar challenges:2) Agricultural pollution
Nitrate concentrations legally OK
But all our large reservoirs are eutrofized
Map of the trophic state of more 10 hm3 reservoirs (Libro blanco del agua, 2005)
We have a problemwith the law
And we face similar challenges:3) Seawater intrusion in all our Med aquifers
SWI causes not only salinization of costal aquifers, but also the loss of submarine groundwaterdischarge, which affects coastal ecosystems
(IPCC, 2018)
And we face similar challenges:4) Rainfall is dropping due to climate change
The Upper Guadiana case
• Relevant because overpumping for irrigationwas causing– The drying of an important wetland (Tablas de
Daimiel) and only fed by surface water– The loss of the Guadiana River
For proper understanding, we built a «fancy» coupled groundwater surface water model
The only input to the model are wheather variables (rainfall, moisture, temperature, etc.) and pumpingrates and soil use
(Sapriza et al, WRR, 2015)
The model reproduces the fall of heads, and Guadiana River and Daimiel wetland drying…
The some 60 m drop in heads, starting in the 1970’s, therecovery of wet years and
reduction in pumping (Sapriza et al, WRR, 2015)
We addressed the impact of climate changeby looking for changes in circulation paterns
1. Find which GCMs did best during historicalrecords.
2. Calibrate during the historical record therainfall for each circulation pattern
3. Examine the future by simply assuming thatthe GCMs produce reliable circulationpatterns
We had to downscale for accuracy
Response to Climate Impacts: GCM historical (1960-1999 Green) and GCM-RCP85 (2060-2099 Red)
So, we went to the Guadiana River Basin Authority (the President was a classmate)
Response:1) We are forced to use the «legal» climate change
projections 2) We cannot enforce water use3) What we do is to buy (i.e., rent) yearly water rights
(which had been appropriated, contrary to Spanish law)
8-7-20111-3-2005
(1) Past situation of «ojos»
Has it worked? Google Earth images
13-11-201528-5-2015
(2)
(4)
(3) 2011 2012 2013 2014 2015 20166
10
14
18
Prof
undi
dad
(m)
“Ojos”Startflowing
Image 2
Image (1)
04.04.263
GW head recovery
It has dried again (because of drought and economic crisis), ….
But we are close!
Second case: the Llobregat Delta suffered severe seawater intrusion threatening the water supply of Barcelona
Again, we calibrated (1965-2001) and validated (2002-2004) a fancy numerical model
Also for salinity
The state of salinization was bad
1995
And it could get much worse
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
After 36 years of pumping
Proposed actions: Reduce pumping and adopt corrective measures to increase resources
Pumping well 1
Pumping well 2
ARTIFICIAL RECHARGE PONDS
2 recharge pondsToral area = 11 haProjected infiltration rate = 0.25 m/d
Total projected recharge =11hm3/y
SEAWATER INTRUSION BARRIER
Divided in 4 sectors+ 2 pumping wells (extract trapped salt)
Total injection rate = 3.65 hm3/y
Recharge pond 1
Recharge pond 2
We posed the problem as an linear programing problem
3
8387.962
3598.126
1912.000
17050.812
14780.677
4334.562
3866.931
10402.932
91976.839
10312.991
153982.228
122613.720
1490316.985
477642.604
477642.604
-25 - -12 hm3/y -12 - -9 hm3/y -9 - -6 hm3/y -6 - -3 hm3/y -3 - -1 hm3/y -1 - 0 hm3/y 0 - 0.01 hm3/y 0.01 - 3 hm3/y
122613. 720
1490316.985
477642.604
477642.6 04
8387.962
3598.126
1912.000
17050.812
14780.677
4334.562
3866.931
10402.932
91976.839
10312.991
153982.228
1
2
3
4
5
122613. 720
1490316.985
477642.604
477642.6 04
8387.962
3598.126
1912.000
17050.812
14780.677
4334.562
3866.931
10402.932
91976.839
10312.991
153982.228
1
2
3
4
5
6
Maximize pumping subject to:1) high heads at the shore, to prevent SWIand 2) fixed artificial recharge rates
Results: unacceptable without corrective actions
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6
hm3 /y
y
Without corrective measures
8387.962
3598.126
1912.000
17050.812
14780.677
4334.562
3866.931
10402.932
91976.839
10312.991
153982.228
122 613. 720
1490 316. 98 5
477 642 .60 4
4 7764 2. 604
1
2
3
4
5
6
Reference pumpingOptimal pumping
-15.00-10.00-5.000.005.00
10.0015.0020.0025.0030.0035.00
Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Ponds Barrier
hm3 /y
y
8387.962
3598.126
1912.000
17050.812
14780.677
4334.562
3866.931
10402.932
91976.839
10312.991
153982.228
122 613. 720
1490 316. 98 5
477 642 .60 4
4 7764 2. 604
1
2
3
4
5
6
But the most interesting results where the shadow prices (hydraulicefficiency)
ARTIFICIAL RECHARGE PONDS = 0.6 SEAWATER INTRUSION BARRIER = 1.7
With corrective measures
Results: OK with corrective actions
The end of the story
1) The seawater Intrusion Barrier was built, but with osmotized water (a negative influence of California!!) so it stopped operation during the crisis
2) The Groundwater Users community did not want to hear of “imposed” pumping reductions, but they adopted the model have been using it themselves for self-control
3) SWI has been controlled
In summary
• Reliable models are possible. Do not trust GCMs forrainfal, but for circulation patterns
• The present is not bad for the people (good quality watersupply, good agricultural production).
• But the present is concerning for water dependentecosystems (rivers in poor shape, depleted coastalecosystems)
• Water rights, often appropriated (not acknowledged bythe law), often exceed availability
• The administration lacks tools to enforce «scientific» allocation plans.
• What works are «user’s communities» and the «rental» of water rights.