EO data to support the optimal

management of irrigation water in

western Morocco:

Potential of sentinel-2 type observation

Kamal LABBASSI

Chouaib Doukkali University

Morocco

DOUKKALA:

downstream portion of the hydraulic basin OR

The research activities are

conducted under the Tiger Project

(www.tiger.esa.int)

PLAIN OF DOUKKALA:

estimate the CWR to contribute

to the rational management of

water of irrigation.

The irrigated area of Doukkala is among the

largest and earliest developed areas in

Morocco, remarkable for its sand strategic

importance for national production, specially

sugar beet (38%) and commercialized milk

(20%).

The region's climate is typically semi-arid with

a large variability in inter and intra-annual

rainfall. average 316 mm / year.

The resources mobilized for irrigation come

mainly from the dam Al Massira, a major water

storage structure in the basin of Oum Rbia

with a capacity of approximately 2760 Mm3 .

The most dominant irrigation technique is

gravity irrigation.

Problematic Irrigated zone of Doukkala

Decrease of resource

Decrease of groundwater resources by 50% during the last 25 years.

Water resources are increasingly scarce in relation

to high demand and unfavorable weather conditions.

Opportunities to mobilize new resources are almost

unexpected.

>>> The only option currently available is represented by

the recuperation of water losses in irrigation systems, as

well as in agricultural fields

Infrastructure Problems

Problems associated with gravitational irrigation

Problem of illegal pumping in irrigation canal

Approach

Estimation of Crop Water Requirements

FAO-56 Model Analytical Approach

Combination of:

- Satellite images

- Meteorological data

(Rainfall, Temperature, Humidity, Wind and Global Radiation)

- Agronomical data

(Calender of crops, irrigated areas, and water allocations).

Means Used

CDA _zone irrigué de Doukkala (Mosaic Spot _ Nov_2008)

Fr

SB Zr

TG

Sensor

Satellite images used

SPOT 1,2,3,4

December 1994 (Dry year, 2mm)

November 2005 (Normal year, 54.6 mm)

November 2008 (Rainfed year, 58 mm)

December 1994

(Dry year, 2mm)

November 2000 March 2001 July 2001

November 2005

(Normal year, 54.6 mm)

November 2008

(Rainfed year, 58 mm)

CWR values increase from November to March and then relapsed in July, and require

maximum amount of water at the crop development in mid season stage (spring).

The average values varied from 26.85 to 130.3mm.

The maximum was observed In the month of Jully while the minimum was observed in the

month of November.

It was also found that CWR was less in the maturity stage as compared to the initial stage.

Pumping

station

IWR (m 3)

Kc _Wheat

Water

Allocations (m 3)

%

Cuvette SS 279 841 416 246 32.75%

SS gravitaire 2 087 022 3 192 998 34.63%

SS Extension 317 753 469 728 32.35%

BirLabid 2 112 455 1 966 548 6.9%

Peff = 6.26 mm

Cuvette SS 1 237 527 1 031 038 16.68%

SS gravitaire 8 813 445 1 088 786 87.64%

SS Extension 1 031 038 1 409 184 26.83%

BirLabid 9 438 072 7 902 236 16.27%

Cuvette SS 514 239 0 100%

SS gravitaire 3 886 765 212 940 94.5

SS Extension 597 304 0 100%

BirLabid 3 860 794 348948 90.9%

Peff = 2.5 mm

Peff = 0 mm

CWR maps ( Kc_mean = 50% Kc_Wheat + 25% Kc_S.Beet + 25% Kc_alfalfa )

In 1994 and 2000 the CWR is relatively high with mean

values between 22 and 46. A slight increase from 1994 to 2000.

Higher values are distributed uniformly in all sectors in 2000

while in 1994 they are limited in the area BirLabid

In 2005 and 2008 the CWR goes down significantly and

sometimes show negative values in 2008.

The highest importance of CWR tend to locate the northern

part of the sector.

Dec. 1994 Nov. 2000

Peff = 2.5 mm

Nov. 2005

Peff = 27,42 mm

Nov. 2008

Peff = 29,35 mm

No data

6 045 520

1 116 749

1 202 577

9 008 449 4 787 071 1 912 679 2 179 491

---

20.8%

41.61%

44.8%

Peff = 0,89 mm

46% 60% 13%

83% 7%

CWR maps ( Kc_mean = 50% Kc_Wheat + 25% Kc_S.Beet + 25% Kc_alfalfa )

Décembre 1994

Novembre 2005

Novembre 2008

Maximum values of CWR

range between 16,06 and 22,36.

CWR increase with the lack of

precipitation and the increase of

crop evapotranspiration

Maximum values of CWR vary

between -33,86 et -19,81.

CWR is very low (November) due

to high precipitations (54,6 mm)

CWR between -32 et -18,40.

CWR are weak du to high

precipitations (November , 58mm).

SB

TG

Zr

Fr

FAO-56 Model

Surface albedo r can be determined easily by using values of reflectance corrected for atmospheric effects, pλ:

With: λ = 1, 2, 3, 4

sensor + band

Eλ° (W/m².um)

Wλ

Spot 4 XS1 1851

0.3925

Spot 4 XS2 1586 0.3339

Spot 4 XS3 1054 0.2240

Spot 4 XS4 240 0.0496

Analytical Approach

The Albedo

In december 1994, the maximum values of albedo range

between 0.14 and 0.29, to attain higher values in

November 2005 and 2008.

Analytical Approach

Climate Parameters Dec

1994

Nov 2005 Nov 2008

Rns: net solar radiation - - -

rc : surface resistance - - -

ra: Aerodynamic resistance - - -

Λ latent heat of vaporisation (MJ/Kg) 2.26 2.26 2.26

∆ slope of vapour pressure curve (Kpa/°c) 0.04 0.04 0.03

Rnl :net long wave radiation (MJ/m2.d-1) 3.70 8.53 8.92

G: soil heat flux -0.406 -0.819 -0.882

De: vapour pressure density 0.09 0.15

0.11

Atmospheric density 1.19

1.19

1.19

Psychometric constant 0.066 0.066

0.066

Dry year (2 mm

Reference year

(54.6 mm)

TG

Fr

SB

Zr

Wet year (58 mm)

~ 2005

SB

TG

Zr

Fr

high value in the central corridor of the irrigated zone ( sugar beet area: northern part of the unit

ZR and unit SB)

low values in the east and west of the irrigated area (wheat areas)

% Water

Allocations

26.5% 24% 16%

19%

3%

7%

20 071 494

14 747 492

Conclusion perspective

use satellite data has enabled to highlight new information on the irrigated zone and to

make a link between large trends in terms of cultures, evapotranspiration and water

requirements in relation with rainfall and allocations (is a new approach, never used in the

region)

The comparison of water allocations and values estimated by the CWR, confirms the

results of measurements on the satisfaction of needs of crops, with a new contribution to

the spatial vision of the phenomenon.

Remote Sensing and GIS integrated approach can be used for estimation of crop

water requirement and irrigation water requirement.

the Crop water requirement was higher in the vegetative and mid-season stage and

shows decreasing trend towards the maturity stage.

it was found that irrigation water requirement highly correlated with crop water

requirement

The approach will be used for other spatial and temporal scales of observation:

- The methodology will be applied on a farm taking into account the type of crop

(winter crop: wheat, summer crop, and throughout the year: Sugar Beet)

- Should be expanded and generalized to on other irrigated areas of the basin (OR)

-Statistical processing of measurement and analysis to establish a logical relationship

between CWR and water allocation

-introduction of new types of data! (With more in spectral and temporal)

In the futur….

Abstract Submission 30 April 2012

Acceptance Notification 30 June 2012

Final paper submission 01 September 2012

IMPORTANT DATES

www.aarse2012.org

9TH INTERNATIONAL CONFERENCE OF THE

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OF THE ENVIRONMENT (AARSE)

October 29 to November 2,

EL JADIDA, MOROCCO

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See you in El Jadida in October 2012