Brief introduction to DRIFT

Downstream Response to Imposed Flow Transformations

History• Development began in 1998

• Examples of applications:– 1998-2002: Lesotho Highlands Water Project

– 1998-2014: 19 river system in South Africa

– 2006: Zambezi Delta (Mozambique), funded by the International Crane Foundation and the Carr Foundation

– 2007: Mzingwane River (Zimbabwe), funded by IUCN

– 2007: Phuthiatsana River (Lesotho), funded by Lesotho Department of Water Affairs

– 2006-9: Pangani Basin (Tanzania), funded by IUCN and the Tanzanian government

– 2008-9: Nile River (Sudan), funded by the Sudanese Dams Implementation Unit

– 2008-10: Okavango Basin (Angola, Namibia, Botswana), funded by GEF/UNDP

– 2009-10: Lower Zambezi River (Mozambique), funded by Riversdale Mining

– 2009-10: Kunene River (Namibia and Angola), funded by the Angolan and Namibian Governments

– 2010-11: Neelum-Jhelum River (Pakistan), funded by the Government of Pakistan

– 2011: Kagera River (Nile Basin), funded by the Nile Basin Initiative

– 2011: Huaura River (Peru), funded by SN Power

– 2013-14: Poonch River (Pakistan), funded by Mira Power

– 2014: middle Zambezi River (Zambia and Zimbabwe), funded by the Zambezi River Authority

– 2015: Lower Mekong River (Laos, Thailand, Cambodia, Vietnam), funded by the Mekong River Commission

– 2016: Elephant Marshes, Shire River (Malawi), funded by Malawi Ministry of Water Development and Irrigation.

• Recognised as a good practice methodology by the World Bank, ADB, IFC, IUCN, OKACOM, and the South African, Tanzanian and Pakistan governments

Pangani River

Zambezi River

Okavango RiverCunene River

Nile River

Huaura River

Pongola River

Mekong River

N-J Basin

Location of applications

c. 50 projects in total

Cuanza River

Trishuli River

Kouilou-Niari Rver

Kagera River

Orange/Senqu Basin

Olifants-Doorn Basin

Berg Basin

Pungwe River

Poonch River

Shire River

For a project of the magnitude of the KishengangaHydropower Project, the Court is of the view that an in-depth assessment of the type that Pakistan has attempted for these

proceedings is an appropriate tool for estimating potential changes in the downstream environment.

Verbatim: In the matter of the Indus Waters Kishenganga arbitration

The International Court of Arbitration constituted in accordance with the Indus Waters Treaty 1960December 2013

The Hague: Permanent Court of Arbitration (December 2013)

Step 1: Select scenarios

Baseline

Scenarios

Generic steps in DRIFT

Step 3: Model hydrology, hydraulics

Step 5: Assign Baseline Status and trends

Step 6: Knowledge captureSet up DRIFT all sites

Create response curves

Step 7: Calibration

Step 8: AnalysisRun DRIFT for all scenarios and generate prediction of change

Step 4: Indicators

Step 2: Select focus areas

Step 1: Scenario selection

• Scenarios are a means of exploring possible pathways into the future

• Describe a range of potential development of the river (design, location and operation of infrastructure/abstractions)

• Dedicate process for scenario selection

• Informs site and indicator selection

Step 2: Site selection

• The sites are the focus for the DRIFT predictions of ecosystem change

Step 3: External modelling

• Time-series of simulations for baseline and each scenario, at each site:

– Hydrology

– Hydraulics

– estimated sediments

• Imported into DRIFT

Step 4: Status and Trends Assessment

• Status and Trends:

– describe the ecological status of the rivers at the time of the study;

– describe the past ecological status of the rivers, and possibly;

– describe the future ecological status rivers with and without the water-resource developments included in the scenarios

• Status of the rivers at the time of the study is most frequently used as the baseline from which to describe change

– Relative change is predicted – no absolutes

Step 5: Indicator selection

• DRIFT indicators are inputs to the DRIFT model

• Each indicator must have a describable relationship to the flow or sediment regime

• Indicators describe:

– the flow regime of the river, e.g., duration of

the dry season

– ecosystem attributes; e.g.; abundance of white fish

– river-linked social attributes, e.g., riverbank gardens

• DRIFT will predict how each indicator will change from baseline

Step 6: Mapping of indicator links

• Map links between driving and responding indicators

Step 7: Knowledge Capture

Each mapped link requires a response curve

Construct the response curves

-5

-4

-3

-2

-1

0

1

2

0 100 200 300 400

Dry season duration (days)S

ev

erit

y r

atin

g in

dic

ati

ng c

ha

nge

in a

bun

da

nce

Response Curves

• Means of capturing information and understanding:– from in-depth scientific data, international

knowledge, national knowledge or local wisdom. – created by EF specialists with a working

knowledge of the river ecosystem and its users– graphic and explicit with supporting explanations– allow qualitative as well as quantitative

knowledge to be captured;– amenable to adjustment as knowledge

increases.

Severity

rating

Severity

change

Equivalent Loss or gain

5 Very large 501-∞ (to pest

proportions)

4 Large 251-500

3 Moderate 68-250

2 Low 26-67

1 Negligible 1-25

0 None No change

-1 Negligible 0-20

-2 Low 20-40

-3 Moderate 40-60

-4 Large 60-80

-5 Very large 100-80

Example: Response Curve

Fish Guild A

-5

-4

-3

-2

-1

0

1

2

3

4

5

0 10 20 30 40 50 60 70 80

Dry Season Minumum Discharge

Sev

eri

ty o

f c

han

ge

rela

tiv

e t

o P

D M

edia

n

specialists draw curve

Response of one ecosystem indicator (Fish Guild A) to minimum dry-

season flows in a year

Specialists construct curve

150 000 t/day > median

c. 25% increase

150 000 t/day < median

c. 20% decrease

230 000 t/day > median

c. 45% increase

The higher the wet season average sediment load, the more river energy

that is expended carrying sediment, and the lower likelihood of erosion.

10 weeks later median

c. 15% decrease

6 weeks earlier median

c. 15% increase

2 weeks later median

No change

The onset of the dry season represents a time rhithron species are able to

migrate to shallower areas with suitable substrate for spawning, earlier onset

allows the fish greater time to migrate but late onset can distrupt spawning

migration and maturation. Also if dry season starts earlier, it beneficial as fish

can mature in less stressful conditions prior to spawning.

Step 7: Calibration

• Refine Response Curves using the historical flow record, so that DRIFT outputs reflect current understanding and monitoring data

• Use a series of calibration sequences to further refine the response curves, e.g.:– Sequence of wet years– Sequence of dry years– Sequence of several dry years, followed by several

wet years, repeated

• Calibration increasingly stabilises the model

Step 8: Analysis

• For each site under each scenario:– Enter input time-series into DRIFT (hydrology,

hydraulics, sediments)– Define other concerns for scenarios (barriers,

management, etc.)– Calculate the values for all input indicators– Run DRIFT to pass input indicators through the

ecosystem response curves– Generate predictions of change for each indicator and

overall ecosystem condition

• Post-process results into report format

Each responding indicatorModelled time series

Transformed into time series of

driving indicators

Fish Guild A

-5

-4

-3

-2

-1

0

1

2

3

4

5

0 10 20 30 40 50 60 70 80

Dry Season Minumum Discharge

Sev

eri

ty o

f c

han

ge

rela

tiv

e t

o P

D M

edia

n

Scenario: Dry season minimum discharge for each year

External modelled time series

Transformed into time series of

driving indicators

DRIFT prediction of

change for each year

30 years of record = 30

values

Each responding indicator

Curves combined using multi-criteria decision analysis procedures

Resp

on

se c

urv

es f

or

ea

ch

lin

ke

d ind

icato

r

Time-series of change

in indicator A

VegetationHydraulics

Macroinvertebrates

Geomorphology

Modelled hydrology time-series

Linked indicators for Indicator A

Depth

Velocity

Temperature

Macroinvert spp.

Marginal vegetation

Sandy banks

Modelled sediment time-series

Modelled water quality time-series

Indicators and Linked Indicators

Examples of DRIFT outputs

Time-series of change for one indicator at one site under fifteen

scenarios

Change in indicator abundance under each scenario, colour-coded to show

severity of changeEcosystem Indicators

KMax

K3.9

4

K10

K20

K40

K60

K100

K7E3

K9E1

Geom

orph

olog

y

Secondary channels, backwater -49.60 -39.43 -29.78 -24.07 -10.75 -9.81 -9.00 -30.39 -41.13

Cobble and boulder bars 13.96 12.62 10.87 5.12 1.52 2.74 1.96 10.83 12.87

Sand and gravel bars -20.19 -21.18 -22.15 -26.52 -24.45 -22.26 -21.59 -22.25 -21.05

Bed sediment size 10.21 11.81 13.56 16.25 20.06 18.74 17.38 13.54 11.52

Active channel width -9.31 -9.31 -9.31 -9.31 -6.72 -4.71 -4.15 -9.34 -9.32

Depth of pools 3.29 3.29 3.29 3.32 4.90 5.52 5.19 3.29 3.28

Wat

er

qual

ity

Dilution of pollution loads -30.89 -23.37 -12.55 -3.26 -2.97 -2.86 -2.69 -20.16 -27.24

Temperature -47.05 -33.00 -2.66 0.42 0.34 0.34 0.36 -23.67 -42.74

Rive

rine

vege

tatio

n Algae 5.28 7.08 8.53 4.43 2.03 2.43 2.43 7.97 6.23

Marginal vegetation 4.50 4.51 4.50 4.51 1.67 -0.79 -0.78 4.52 4.51

Natural terrace veg. -3.57 -3.57 -3.57 -3.60 -3.62 -3.62 -3.62 -3.61 -3.57

Mac

ro-

inve

rteb

Simuliidae 4.79 6.48 9.06 4.35 5.28 5.00 4.79 7.43 5.24

Other flies & midges 21.92 21.62 20.42 10.62 9.71 9.94 10.24 21.29 21.67

EPT abundance -42.70 -29.13 -10.00 -2.90 5.64 5.38 5.77 -22.41 -35.66

Fish

Brown Trout -76.92 -50.55 -1.14 5.51 9.54 14.45 19.15 -36.66 -66.64

Tibetan Snow Trout -74.68 -59.15 -38.12 -29.24 -19.09 -18.50 -15.08 -51.86 -67.11

Alwan Snow Trout -64.15 -44.76 -22.04 -13.10 -13.23 -14.06 -12.17 -37.57 -53.57

High Altitude Loach -79.06 -72.82 -49.03 -34.98 -20.48 -20.09 -16.96 -65.54 -76.79

K. Hillstream Loach -78.84 -72.33 -50.85 -41.91 -25.43 -24.46 -21.85 -64.93 -76.49

Himalayan Cat Fish -36.56 -23.63 -9.02 -8.00 0.10 0.19 0.61 -18.51 -29.28

Change in ecosystem condition (integrity) at a site under scenarios

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

PD

MA

MD

HW

K5

N9

K1

0N

9

K2

0N

9

K4

0N

9

K6

0N

9

K8

0N

9

K1

00N

9

KH

5E

5N

9

KH

7E

3N

9

KH

9E

1N

9

KM

DN

9

KH

WN

9

K3

94N

9

KM

D3N

9

KM

D4N

9

Ove

rall in

teg

rity

sco

re w

ith

Min

an

d M

ax (

LO

C)

Scenarios

Integrity A to B B to C C to D D to E E to F

A

B

D

E

C

Present Day Medium High

A

D

BC

ENot assessed

Low

Snapshot of basin-wide ecosystem condition under different scenarios