Contract number: 031A249A Work package number 4 June 2015 Deliverable 4.4.2 Water resources situation in CSS General conditions of water resources in Kilosa and Chamwino district and expected implications for agricultural and food security strategies Meike Pendo Schaefer, Ot tfried Dietrich Institute of Landscape Hydrology Leibniz Centre for Agricultural Landscape Research (ZALF) Müncheberg, Germany Public use Yes Confidenal use - - - 1 Inhalt Introducon ....................................................................................................................................................... 3 Overview of study area ( ami river basin) ....................................................................................................... 4 Current status of water resources in case study sites ....................................................................................... 6 Chamwino district (Kinyasungwe sub-basin) ................................................................................................. 6 Kilosa district (M)ondoa sub-basin) .............................................................................................................. 9 E,pected future developments in case study sites ......................................................................................... 13 Implicaons for agricultural food security strategies ...................................................................................... 19 .upplementary notes ...................................................................................................................................... 22 Appendi, 10E,isng and proposed reservoirs in ami12uvu river basin ........................................................ 23 Appendi, 20.oil ater Management Pracces (. MP) ................................................................................. 24 Appendi, 30Monthly water balance calculaon for Kinyasungwe 3 M)ondoa rivers ..................................... 26 2eferences ....................................................................................................................................................... 27 2 General conditions of water resources in Kilosa and Chamwino district and expected implications for agricultural and food security strategies Introduction The present report was compiled in frames of the Trans-.EC pro6ect, which aims at improving the food situaon for the most vulnerable rural poor populaon in Tan8ania through the idenficaon and disseminaon of successful upgrading strategies (9P.) for small-scale agricultural producon. 2esearch for the Trans-.EC pro6ect is implemented by a large consorum of e,perts from a range of polical, social, economic and natural resources bac)grounds to cover the comple, realies of agricultural producon in rural Tan8ania. The tas) of the hydrologic work group is to provide an assessment of the state of water resources and e,pected future developments, and to evaluate the implicaons for agricultural food security strategies. It also invesgates how large-scale implementaon of 9P. would a:ect water resources in the pro6ect region. In a first step, a comprehensive literature review was conducted to gather an understanding of the processes a:ecng water resources on drainage basin and regional scale in Eastern and .outhern Africa. It also provided the frames for placing observed changes and pressures within a larger regional and temporal conte,t, which is especially important for the assessment of future developments and also recommendaons of acon. As it became apparent, Tan8ania lies within a 8one of strong hydrologic changes and reportedly high pressure from driving forces such as populaon growth, agricultural sector development, and climate change. In many cases, water demand already e,ceeds water availability, thus liming food producon and agricultural development (Besada 3 erner, 2015; Gunase)ara, Ka8ama, Yama8a)i, 3 O)i, 2014). The ami drainage basin, which is the site of the pro6ect field trials in Tan8ania, is no e,cepon to this case. In a second step, therefore, informaon on the concrete state of water resources in the sub-basins of the Trans-.EC case study sites was compiled. The findings described in the following secons are drawn from a number of relevant hydrologic sources, most importantly the 2015 “Atlas and 2eports on the ami12uvu 2iver BasinA by Global ater for .ustainability Program (GLO .-CI9), the 2013 “.tudy on ater 2esources Management and Development in ami12uvu BasinA by the Eapanese Internaonal Cooperaon Agency (EICA), and the 2010 “ ami Basin .ituaon AnalysisA by the Internaonal 9nion for Conservaon of Nature (I9CN)). The collated informaon on relevant hydrologic aspects provides important insights on the bac)ground of natural resources against which Trans-.EC is operang, and indicates framewor) condions for the intended 9P.. 3 Overview of study area (Wami river basin) In respect to water resources, the common spaal boundaries are usually drainage basins. A drainage basin is a hydrologic unit which is defined as an area where precipitaon runs o: from the land towards one common point such as a river, la)e or aGuifer. The boundaries of a drainage basin are oHen mar)ed by landscape features such as ridges or mountain Ian)s, which cause a disncve divide of the direcon the runo: is channeled to. 9sually, drainage basins are named aHer the longest-running river or largest la)e within a basin, and can be sub-divided into smaller sub-basins along the tributaries (9.G., 2014; MO, 2012). Drainage basin boundaries are geomorphologically defined and do therefore not e,actly coincide with administrave boundaries. Cigure 1 displays the di:erent spaal boundaries related to in the present report. The four Trans-.EC case study sites (C..) and the respecve wards are located in the ami catchment, while the respecve districts only parally coincide with the basin. The C.. villages in Chamwino district (Ilolo 3 Idifu) are aJributed to Kinyasungwe sub- basin, while those in Kilosa district (Ila)ala 3 Changarawe) are aJributed to M)ondoa sub-basin. Fig. 1: Location of Trans-SEC study sites and associated districts and river basins in Tanzania The ami basin is 43,742)mK large and covers the e,tent of the 637)m long ami river from its source in the Kaguru mountains in the west to its estuary in the Indian Ocean. It encompasses two naonal par)s (Mi)umi and .aadani), parts of the Eastern Arc Mountains (9)agurus and Ngurus), and several protected forest sites; however, none of these are in the direct reach of the C... The elevaon of the basin decreases from west to east, with Chamwino district located at around 1,000-1,300masl, while Kilosa district is around 600-900 masl. The di:erences in elevaon as well as the distance to the sea are the main factors driving the climac condions of the basin, with semi-arid condions in the western and increasingly humid condions in the eastern part (see Cigure 2). The inland receives one rainfall season around December, whereas the rest of the basin has two rainfall seasons with the ma6or one between March-May (“Masi)aA), and the minor one between October-December (“LuliA). Lery liJle rainfall is recorded in the dry season of Eune to .eptember. 4 The ma,imum temperatures are recorded in November M Cebruary and the minimum temperatures are recorded in Eune M August. Average annual temperatures are comparable at around 22-25NC in both regions; however, the temperature range is higher in Chamwino district. Potenal evapotranspiraon is also similar in both districts at around 1600mm1year (GLO .-CI9, 2014c; EICA, 2013b, 2013c). The Iow of the ami river and its tributaries is lin)ed to the described rainfall paJerns. As the basin lies in the meteorological transion 8one between the bimodal and unimodal rainfall regimes, river Iow regimes vary slightly depending on the amount of seasonal rainfall. Most large streams have a defined pea) during the long rains and a second smaller pea) during the short rains, with high Iows during periods of heavy rainfall. The lowest Iow is typically e,perienced in October, but low or no Iow periods e,tend longer for seasonal rivers. The rivers support a number of small- and larger scale irrigaon schemes, but the ma6ority of agriculture is rain-fed. There are no larger industrial comple,es or cies in the C.. vicinity, and the populaon density is about 100 persons1)mK in both Chamwino and Kilosa district (GLO .-CI9, 2014a, 2014c; I9CN, 2010; 2B O, 2008). Fig. 2: Isohyets showing annual rainfall averaged over 1950-2010 Map from Water Atlas of Wami/Ruvu Basin, p.67 (GLOWS-FIU, 2014c) with own edits ( ami river basin is part of the ami12uvu basin; above ami basin is outlined in bold blac), C.. wards in green) 5 Current status of water resources in case study sites Chamwino district (Kinyasungwe sub-basin) Chamwino district is a predominantly rural area, with the vast ma6ority of households engaging in smallholder crop producon and possibly livestoc) )eeping. O:-farm income sources are limited, and the literacy rate is comparably low (63P). Chamwino district encompasses two C.., namely Idifu (Idifu ward) and Ilolo (Muungano ward). Both of these wards together cover appro,imately 230)mK, which is only a small poron of the total 16,483)mK of the Kinyasungwe sub-basin. Both C.. lie along an unnamed ephemeral river a which is a southern-west tributary of the Kinyasungwe river (Cig. 3) (GLO .-CI9, 2014c). Ilolo village is partly within 2ufi6i river basin, but the largest poron drains to the Kinyasungwe river;