Agricultural water supply in the Okanagan Basin – using ... · PDF fileOkanagan Basin...

Agricultural water supply in theOkanagan Basin – using climate changescenarios to inform dialogue and planning processes

Denise Neilsen, Scott SmithPacific Agri-Food Research Centre, Summerland, B.C.Stewart CohenEnvironment Canada, AIRG – Vancouver, B.C.

http://www.ires.ubc.ca

Expanding the dialogue on water management & climate change in the Okanagan

• Mark Barton, Bill Taylor EC-PYR

• Jeff Carmichael, James Tansey SDRI/UBC

• Andrew Reeder RDOS

• Brian Symonds BCMWLAP

• Younes Alila, Wendy Merritt Forestry/UBCSupported by a grant from the Climate Change Action Fund(#A463/433), Natural Resources Canada, Ottawa.


Water Management & Climate Change in the Okanagan – CCAF Project

• Climate change scenarios

• Hydrologic modeling (water supply)

• Agricultural modeling (water demand)

• Population Growth• Adaptation Options

• early adopters• costs• stakeholder dialogue

Supported by a grant from the Climate Change Action Fund(#A463/433), Natural Resources Canada, Ottawa.


Okanagan water supply

‘The Okanagan Basin has the lowest, per capita availability of freshwater in Canada’Statistics Canada. 2003. Human activity and the environment. Annual Statistics 2003. Cat. No. 11-509x XPE


Okanagan Basin – Snow melt watershed with semi-arid climate

April/04

Supply depends onstorage in

• upland reservoirs

• mainstem lakes

• ground water (limited)


Water Purveyors

Fragmented water supply system

• 53 public

• 3 large private

• 1147 small private


Agricultural land in the Okanagan basin

• created 1972

• protects agricultural land

• applications for removal to Agricultural Land Commission

• unirrigated – range

• irrigated – all crops


Irrigated agriculture in the Okanagan Basin

• high value horticulture

• pasture/forage


Range of water management practices


Agricultural vulnerability: competition for water and land

• highly controlled• flood

• fish• water supply

• agriculture 70-80% of diverted water

• municipal

• recreation

• urban development

• trans-boundary requirements


Winter Season (DJF) 2050, Lat=50o Lon=120o

0

5

10

15

20

25

0 1 2 3 4 5

Mean Temperature Change (oC)

Pre

cipi

tatio

n C

hang

e (%

)

Summer Season (JJA) 2050, Lat=50o Lon=120o

-40

-30

-20

-10

0

10

0 1 2 3 4 5Mean Temperature Change (oC)

Pre

cipi

tatio

n C

hang

e (%

)

Six climate change scenarios at three time slices (2020s, 2050s,

2080s)

CGCM2 A21

CGCM2 B21

CSIROMk2 A21

CSIROMk2 B21

HadCM3 A22

HadCM3 B22

Legend

Winter 2050s

Summer 2050s


Climate change scenarios (18)

1. GCM-adjusted baseline• ∆T, ∆p – monthly differences between future projection and

baseline climate (1961-1990) - add ∆T, - % change for ∆p

2. Normals model• Apply to 1961-90 normals for station data or gridded data sets

(PRISM 1x1km): • Interpolate to daily temperatures using cubic spline (Morrison

(1998)

3. Inter-annual model• Apply to 1961-90 daily for station data:

• Temporal and spatial interpolation by cubic spline


Hydrology model

UBC – watershed model (Quick, 1995)• Semi-distributed conceptual model• Meteorological data distributed to series of

elevation bands • Parameterization of ungauged tributaries

with data from gauged, unregulated tributaries

• Aggregates sub-watersheds

Source: Wendy Merritt & Younes Alila, 2004


Impacts on Water Supply

Modeled SWE for Pearson Creek catchmentbased on Joe Rich Creek

0

100

200

300

400

500

600

700

1961 1971 1981 1991 2001 2011 2021 2031 2041 2051 2061 2071 2081 2091

SW

E (m

m)

BaseCGCM2 A2HadCM3 A2CSIRO A2

• Reduction in snow pack

Source: Wendy Merritt & Younes Alila, UBC – UBC Watershed Model


Impacts on Water Supply

• More rain dominated hydrograph

• Change in volume of peak flows

• Earlier peak flows• Earlier recessionImplications for water

users –• less in-stream flow• earlier withdrawal from

storage

Source: Wendy Merritt & Younes Alila, UBC – UBC Watershed Model


Data required for modeling crop water demand-using GIS

• Spatial distribution of climate data (griddeddatasets at fine scale 1x1 km)

• Derived relationships between evapotranspirationand actual crop water use for different crop types

• Derived relationships between climate data and estimates of potential evapotranspiration

• Length of growing season based on degree day accumulation (for indeterminate crop types)

• Spatial distribution of crops


Model Structure

Prism grid 1 x 1km

Water purveyor boundary

Crop polygon

Accumulation of crop water use1. Crop polygon

• mm water use x polygon area (ha) = m3 x 102. Sub-watershed

• Sum of crop polygons3. Water Purveyor

• Sum of crop polygons4. Basin

• Sum of crop polygons


Climate Normals Model: Basin crop water use in response to climate change

20

60

100

140

180

220

260

300

340

1961-03 2020s 2050s 2080s 2020s 2050s 2080s

m3 x

106

Historic CGCM2 CSIROMk2 HadCM3

B2A2


Climate Normals Model: Water use in response to climate change – crop

(by crop)Grapes

CGCM2-A21

0

1

2

3

4

1 2 3 4 5 6 7 8 9 10 11 12

Months

m3

x 10

3

historic 2020s 2050s 2080s

AppleCGCM2-A21

0

1

2

3

4

1 2 3 4 5 6 7 8 9 10 11 12

Months

m3 x

103

historic 2020s 2050s 2080sPasture/Forage

CGCM2-A21

0

1

2

3

4

1 2 3 4 5 6 7 8 9 10 11 12

Months

m3 x

103

historic 2020s 2050s 2080s


Climate Normals Model: Basin water supply/demand response to climate change

140

180

220

260

300

340

500 600 700 800 900 1000

Okanagan L. inflow (m3 x 106)

Crop

wat

er d

eman

d (m

3 x 1

06 )

HistoricCGCM2CSIROMk2HadCM3

2080s

2050s

2020s


Agricultural water demand in response to climate change-interannual study

Summerland Case study• integrated system• irrigation currently greater than domestic demand • Trout Creek, 2nd largest flow in basin• fish flow requirements

• 2003-04 municipality and DFO in court over fish flow • municipality facing $1million fine


Variation in crop water demand and Trout Creek flows in response to climate change

Summerland Case study

HadCM3-A2

0

2

4

6

8

10

12

14

0 50 100 150 200 250

Annual flow (m3 x 106)

Cro

p w

ater

dem

and

(m3 x

106 ) Historic

2020s2050s2080s

CGCM2-B2

0

2

4

6

8

10

12

14

0 50 100 150 200 250

Annual flow (m3 x 106)

Cro

p w

ater

dem

and

(m3 x

106 ) Historic

2020s2050s2080s

‘defined drought – 30% average annual flow’

‘max. allowable demand – 2002 use’


Residential water demand in response to population growth and climate change

Penticton Case study• irrigation currently less than domestic demand • three population growth rates

• high = City of Penticton OCP projections• med = 50%• low = 25%

• relationships for indoor/outdoor use developed from 1998-2002 data


Residential water demand in response to population growth and climate change

Average Annual Water Use

0

5000

10000

15000

20000

25000

30000

35000

40000

2001 None CC1 CC2 CC3 CC4 CC5 CC6

Climate Scenario

Aver

age

Annu

al W

ater

Use

(ML)

2001low population growth 2020smedium population growth 2020shigh population growth 2020slow population growth 2050smedium population growth 2050shigh population growth 2050s

PentictonCase study

max. demand irrigation adjusted for climate change

Source: Jeff Carmichael, Tina Neale, UBC – Population case study


Adaptation costs

Adaptation option

% saved or gained

Cost/acre-foot

Who pays

Irrig. Sched. 10 $500 –835 Producer

Trickle Irrig. 30 $500-1666 Producer

Education 10 $835 Taxpayer

Metering 20-30 $1880-3400 Taxpayer

Mainstem pump.

0-100 $648-2700 Taxpayer

Storage limited $1500 Taxpayer

Source: Roger McNeil EC PYR and Bob Hrasko


Adaptation issues – current/future

• Insufficient water supply

• Increased agricultural demand

• Increased population demand

• Fragmented water management responsibilities


Stakeholder views on adaptation:(2003/4 Basin wide)

Engaging dialogue to identify opportunities and challenges for basin-wideimplementation of adaptation strategies to scenarios of streamflow reductions and increased demand in the Okanagan Basin need• integration with local growth strategies; • local ownership of solutions • sense of belonging to the basin• support for expanded role for OBWB • financial support needed from all levels of government

Institutional challenges?• clearly defined mandates to manage water quantity • integratation land use plans with long term water management needs

Scaling up from community to basin...


Adaptation responses – supply side

• 2003 – in response to drought, number of W.P. applied for licences to withdraw from mainstem and groundwater

• consideration of increased upland storage

• separation domestic/irrigation delivery systems


Adaptation responses (water purveyors) –demand side

• Water management advisors hired in several districts

• Bylaw enforcement including shutoff after number of violations

•Metering options - SEKID model being considered


SEKID - Water management through education and metering

Difference between water required and used

Water us

e report

Source: Ted van der Gulik, Peter Parchomchuk, Toby Pike SEKID project


Adaptation issues – NGO/institutional responses (2004-

• Okanagan Partnership – recently formed group of members of the business,academic and government communities to study and stimulate Okanagan economy

• Major issues identified• Need for integrated water and land use planning• Need to retain agriculture as the ‘backdrop’ of the community


Water Purveyors

Consolidate fragmented water supply system

• 53 public

• 3 large private

• 1147 small private


Local governments

Incorporate climate change information into planning process

Osoyoos

Oliver

PentictonSummerland

Kelowna

Vernon

Okanagan ValleyPARC GIS July 2004

Kamloops

Legend

Urban

First Nations

Okanagan Watershed

Urban – municipalities

Rural – regional districts

First Nations

Municpalities


Adaptation by agriculture – demand side

• change crop profile to crop with lower demands • e.g. irrigated hay pasture ⇒ grapes, tree fruits

• more efficient irrigation practices• micro-irrigation • mulching• deficit irrigation • improved irrigation scheduling (e.g. fully automated)


Concerns of agricultural water users

• water currently saved by agricultural conservation will be re-allocated for development and not ‘banked’ for future shortfalls


Climate change: We are at risk

Report to the standing committee on Agriculture and Forestry, 2003

Seven recommendations were made• No. 3:

‘Research on water be made a national priority, with a special focus on “supply and demand” scenarios, water management and planning at the local level, and adaptation options including infrastructures’


Thankyou

http:// www.ires.ubc.ca

Agricultural water supply in the Okanagan Basin – using ... · PDF fileOkanagan Basin...

Documents

Transcript of Agricultural water supply in the Okanagan Basin – using ... · PDF fileOkanagan Basin...