Variability of rainfall regime in an agricultural region with a semi-arid climate: Case of Tadla irrigated perimeter (continental Morocco)

Document Type: Research Paper

Authors

Environmental Engineering, Faculty of Science and Technology -University Sultan Moulay Slimane, Béni Mellal, (Morocco)

10.22124/cjes.2021.4305

Abstract


The perimeter of Tadla, a strategic irrigated agricultural area in Morocco, but its rainwater resources are becoming scarcer. In fact, this work aims to study by relevant methods of rainfall variability in this perimeter, with a semi-arid climate, using 60 years (1958-2018) of data from the local network of 27 weather stations.  Drought threshold is determined at 243 mm/year and the rainfall deviation index reaches -11%. Reduced centred indices provide information on equity in surplus, normal and deficit years of rainfall and that three successive periods corresponding in rainfall dominance to number: 13, 8 and 39 years; that Hanning's second order low-pass filter weighting maintains proportionalities but advances them by ten years. Mann-Kendall test also approves rainfall decrease; Sen's test gives a negative average trend slope. In addition, statistical tests for the detection of chronological rupture (Pettitt test, Lee and Heghinian bayesian method, Buishand U statistic, Hubert segmentation) detect the break in 1978 and lead to observations after rupture in reduction of 36 % in rainfall, increase in the frequency of deficit years at the expense of surplus years and mapping on a spatio-temporal distribution of precipitation of three homogeneous areas, including isohyets more displaced according to drying from west to east. Our results characterizing deep regional climate changes as rainfall are useful in programming resilience or adaptation to rainwater scarcity in such vulnerable agricultural biotopes.

Keywords


Abdou, A, Thierry, L & Abou, A 2008, Signification et usage de l’indice pluviométrique au Sahel. Journal Sècheresse, 19: 227-35.

Assani, AA 1999, Analyse de la variabilité temporelle des précipitations (1916-1996) à Lubumbashi (Congo-Kinshasa) en relation avec certains indicateurs de la circulation atmosphérique (oscillation australe) et océanique (El Niño/La Niña). Science et changements planétaires. Journal Sécheresse, 10: 245-252.

Boyer, JF 1998, Khronostat statistical time series analyses software. Montpellier : UMR 5569. Hydrosciences, IRD-Maison des sciences de l’eau. Website:http://www.hydrosciences.org/spip.php?article1000. “KHRONOSTAT software”

 Braumer, J S 1997, Non-parametric estimation of slope: Sen’s method in environmental pollution, Environment Sampling & Monitoring Primer inEnvironmental Pollution at website: http://www.cee.vt.edu/program; areas/environmental/teach/smprimer/sen/sen.html.

Buishand, TA, 1984, Tests for detecting a shift in the mean of hydrological time series. Journal of  Hydrology, 73: 51-69.

Dagnelie, P 1970, Théorie et méthodes statistiques. Editions Duculot. Gembloux / Belgique (Belgium), Vol. 1, 378 p.,  Vol. 2 : 451 p.

El Ajhar, L, El Khachine, D, El Bakouri, A, El Kharrim, K & Belghyti, D 2018,  Evolution de la pluviométrie de 1960 à 2015 au Maroc. International Journal of Research Science and Management, 5: 47-56.

Faty, A, Kane, A & Ndiaye, AL 2017,  Influence de la manifestation climatique sur les régimes pluviométriques saisonniers dans le haut bassin versant du Sénégal. Revue des sciences de l’eau / Journal of  Water Science, 30: 79‑87.

Fossou, R M N, Lasm, T, Soro, N, Soro, T, Soro, G, De Lasme, OZ, Baka, D, Onetie OZ & Orou, R 2015,  Variabilité climatique et son impact sur les ressources en eaux souterraines : Cas de stations de Bocanda et de Dimbokro au Centre-Est de la Côte d’Ivoire (Afrique de l’Ouest). Larhyss Journal,  21, 97-120.

GIEC 2013, Les changements climatiques, les éléments scientifiques. Publication du Groupe d’Experts Intergouvernemental sur l’évolution du Climat (GIEC), 5ème rapport du GIEC, pp : 40-43.

Hubert, P, Carbonnel, JP & Chaouche, A 1989, Segmentation des series hydrométéorologiques : Application a des series de précipitations et de débits en Afrique de l’ouest. Journal of Hydrology, 110: 349-367.

 Jouilil, I, Bitar, K, Salama, H, Amraoui, A, Mokssit, A, & Tahiri, M 2013, Sécheresse météorologique au bassin hydraulique Oum Er Rbia durant les dernières décennies. Larhyss Journal,  12: 109-127.

Kendall, MG, & Steuart, A 1976, The Advanced Theory of Statistics, Vol. 3: Design and Analysis, and Time‐Series, 3rd  Edition, Griffin and Company, London (England), 585 p.

Krimisa, S, Bouchaoui, L & Abouricha, S 2017, Apport des techniques statistiques à l’étude de la variabilité climatique : Exemple du bassin de Tadla-Azilal (Maroc). Larhyss Journal, 30: 7-26.

Lee, AFS & Heghinian SM 1977, A shift of the mean level in a sequence of independant normal random variables - A bayesiian approch. Journal of Technometrics, 19: 503-506.

McKee, TB, Doesken, NJ & Kleist, J 1995, Drought monitoring with multiple times scales. American Meteorological Society, 9th Conference on Applied Climatology, 15-22 January, Dallas, TX, pp. 233-236.

Ministere de l'Agriculture Marocaine 2019, Ressources Hydriques : http://www.agriculture.gov.ma/ ,consulted as of 21 September 2019,(In Arabic, French and English).

Nahli, A, Hebabaze, S, Chlaida, M 2016. Assessment of the physicochemical quality of Hassar stream after installing Mediouna wastewater treatment plant (Casablanca, Morocco), Journal of Materials and Environmental Science, 7: 519-524.

Nicholson, S E & Palao, IM 1993, A Re‐evaluation of Rainfall Variability in the Sahel. Part I. Characteristics of Rainfall Fluctuations. International Journal of Climatology, 3: 371-389.  

OMM (WMO) 2012, Guide d’utilisation de l’indice normalisé de précipitations. Rapport No. 1090 (17 pages) de l’Organisation Météorologique Mondiale (OMM), Edition OMM-Genève / Suisse (Switzerland), pp : 3-11.

ORMVA du Tadla 2019,  Agricultural perimeter monograph. Site web de l’établissement ORMVA du Tadla (Morocco) : https://ormva-tadla.ma/ , consulted as of 21 September 2019, [In  French].

Pettitt A N 1979, A non-parametric approach to the change–point problem. J. Applied Statistiques,  28:  126-135.

Sebbar, A, Badri, W, Fougrach, H, Hsaine, M & Saloui, A 2011, Étude de la variabilité du régime pluviométrique au Maroc septentrional (1935-2004). Science et Changements Planétaires / J. Sécheresse,  22: 139-148.

Sebbar, A, Hsain, M, Fougrach, H & Badri, W 2013,  Carte des précipitations annuelles au Maroc (1935/2006). Proceedings of 26ème Colloque de l’Association Internationale de Climatologie (France),organised in Cotonou (country : Bénin), pp. 37-43, [In  French].

Shepard, D 1968, A two dimensional interpolation function for regularly spaced data. In: Proceedings of                       23rd National Conference of the Association for Computing Machinery, Princeton, NJ, ACM,pp: 517-524.

Taibi, S, Meddi, M, Souag, D & Mahe, G 2013, Evolution et régionalisation des précipitations au Nord de l’Algérie (1936–2009), climate and land surface changes in hydrology.Publications of the International Association of Hydrological Sciences (IAHS), 359: 191-197.

Traore, V, Ndiaye, ML, Mbow, C, Giovani, M, Sarr, J, Beye, A & Diaw, A 2017, KhronoStat Model as Statistical Analysis Tools in Low Casamance River Basin, Senegal. Scientific & Academic Publishing. World Environment, 7: 10-22.