To ensure the sustainability of the water sector, it is necessary to design water investments together with pertinent subdivisions, like agriculture, industry and energy in order to exploit progressive employment and economic results. By implementing an appropriate governing framework, private -public partnerships provide promises for ample desirable deal in the water sectors, comprising constructing and functioning setup for water supply and irrigation, treatment and distribution (Van Leeuwen, 2015; Lund, 2015; UNWWAP, 2016). Reliable natural resources are indispensable for sustainable development. However, infrastructure and technologies of water storage like huge dams could interrupt ecosystem stabilities. Some soft structure (e.g. flood plains, wetlands, and groundwater recharge), moderate walls, harvesting of rainwater, or properly sketched structure are more environmentally profound and economically gainful (Norris and Suomela, 2017; Markolf et al., 2018).
The common property resource theory suggests that increasing scarcity is an incentive for community collaboration, and leads to the evolution of informal water governance and sustainable resource management (Ostrom, 1990). Eight principles of self-governance were developed (Ostrom, 1990; Ostrom and Basurto, 2011) and literature reviews have assessed the effectiveness of community-based institutions in addressing social dilemmas in developing countries, notably in water equity/ efficiency tradeoffs between small-scale upstream and downstream irrigators accessing water from permanent rivers (Quinn et al., 2007; Sjaha and Baldwin, 2014; Caretta, 2015; Weiss, 2015; Mosha et al., 2016). However, little is known on water governance systems in communities living in semi-aridareas where rivers are seasonal. According to Quinn et al. (2007) resource availability dramatically varies by season in semi-aridareas of central Tanzania (Singida and Dodoma): resource users are operating in a complex social and economic system and therefore Ostrom’s principles should not be used as blueprint. These communities depend on run-off waters accumulated in natural and manmade reservoirs, with diverse water extraction technologies used in wetlands and in dry sandy riverbeds. Local resource users (domestic, stock and crop use) also compete and communities face fluctuating water availability, which must affect the development of permanent local institutions. This study therefore sought to carry out a socio-economic analysis of water governance systems in semi-aridareas of the Lake Zone of Tanzania, in order to determine the existence and functioning of informal water governance systems there.
In semi-aridareas of Tanzania vulnerability context is depicted as the starting component for policy process analysis through the sustainable livelihood approach. Giving vulnerability a high prominence in this analysis allowed the research to consider all kinds of vulnerabilities as central issues to the ways in which livelihoods are shaped. Hence the Sustainable Livelihood framework was used in this research as the comprehensive framework for assessing the contributing factors to limited water resources availability to sustain people’s livelihoods. The study revealed that, changes in the quantity, timing, intensity and duration of rainfall as a result of climate change contributes to greater water stress and making people more vulnerable. Due to over-abstraction upstream of the Great Ruaha River, it implies that, people depending on the water resources downstream of the Great Ruaha River catchment are vulnerable. Their livelihoods are at risks as they don’t have water for irrigation and other economic activities. The study also revealed that, both vulnerability and livelihood strategies are derived through natural water availability which features droughts, climate change and the link between water availability, agricultural production, and outcomes.
A BSTRACT : Acacias are spectacular angiosperms grouping single canopy species to those of tropical forests. Easy growth, hardiness and drought resistance of these Australian Wattle trees give them variable and great economic importance. Indeed, among other they produce, wood, edible seeds, gums and provide a valuable source of high quality fodder, rich in protein for subsistence and commercial production of livestock because they provide foliage during dry periods in the absence of herbaceous species. In addition, they contribute to the warmer climate of arid and semi-aridareas by reducing evaporation and creating a shadow that slows the soil drying and provide the setting and coastal sand dunes with their lateral root system that promotes better maintenance of the sand particles cohesion. Moreover, their ability to develop a dual symbiosis with Rhizobium bacteria and mycorrhizal fungi confers ecological importance. Indeed, they provide soil enrichment and improvement of soil fertility due to their ability to fix atmospheric nitrogen and to explore deep horizons of the soil by their roots. All these factors make it an economic resource of a great environmental and social importance, especially in arid and semi-aridareas, and an excellent candidate for reforestation of Mediterranean areas.
Agrobiodiversity is understood as “the variety and vari- ability of living organisms that contribute to food and agri- culture in the broadest sense, and that are associated with cultivating crops and rearing animals within ecological complexes” [1,2]. A sustainable utilization of agrobiodiver- sity and associated ecosystem services through diversified farming systems is advocated to be a robust approach for addressing food security and the sustainability of agricul- tural systems [3-8]. However, how agrobiodiversity is used to address food security and sustainability of agricultural systems in smallholder farming systems in arid and semi- aridareas of West Africa needs to be investigated and documented so as to inform policy decisions. In fact, the challenge of providing sufficient food for the increasing population while preserving natural resources is higher in arid and semi-aridareas [9,10]. In these areas, agricultural production systems are faced not only with persistent water scarcity and frequent drought, but also with high cli- matic variability, land degradation, desertification, and widespread poverty . The strong climatic variations and irregular rainfalls that characterized agro-ecosystems in dry areas make harvest of staple and cash crops highly un- certain, especially in West African Sahel and dry savannas . These constraints are expected to intensify as a result of population growth, urbanization and climate change, which will likely exacerbate food insecurity in these areas, that are already vulnerable to hunger and under-nutrition . In this context, increased knowledge of the function- alities of agrobiodiversity will help build the social and natural science evidence-base to allow formulation of ad- equate intensification strategies . These context- and location-specific strategies require a clear understanding of food production and consumption systems.
Evaporation is difficult to measure experimentally over water surfaces; several techniques and models have been suggested and used in the past for its determination. There exists a multitude of methods for the measurement and estimation of evaporation. Evaporation pans provide one of the simplest, inexpensive, and most widely used methods of estimating evaporative losses. In the present study, the rate of evaporation starting from a water surface was calculated by modeling with application to dams in wet, arid and semiaridareas in Algeria.
From this study, it first appears that the diet of Psammomys obesus is strictly vegetarian at Dzira. Because of the abundance of Amaranthaceae (Salsola tetrandra and Suaeda fruticosa) and Asteraceae (Atriplex halimus), its diet is limited to these two families. However, when these three species are lacking or are scarce, this gerbil finds compensation in the family of Plumbaginaceae, notably all kinds of Limonium and Limoniastrum guyonianum. These species have the advantage of presenting fleshy leaves, gorged with water and salts.
Inhabitants in transient geographic areas located be- tween a sea basin and huge deserts, as the Israeli South is, are especially sensitive to winds. In our region two dominant air streams bring with them opposite changes in the atmosphere [4,21-23]. Wet, fresh, moderate, mari- time breeze renders a sedative action. Hot, dry, highly electrified dusty desert winds bring with them variations in the content and concentration of air-suspended parti- cles, in distributions of Pr, T, RH and other parameters. The instability of every one of these factors or some of them, acting together, may cause aggravation of chronic diseases but especially the worsening of general feelings and occurrence of DS, such as depression, violation of routine behavior, nervous tension, emotional conflicts, etc. [8-11,24-28].
Thus when the cities grow, the dependability of local resources would become too low for water utilities to provide adequate supplies to the municipal users on a sustainable basis. More importantly, the fast growing urban centres in India are located in semiarid and aridareas experience high variability in rainfall conditions, making the supplies from local water bodies such as tanks, and ponds and wells unreliable. Examples are Pune, Ahmedabad, Hyderabad, Chennai, Delhi, Rajkot, Hyderabad and Bangalore. There are very few urban areas that are located in water-abundant regions. In a semiarid or arid area, if the urban centre taps water for municipal uses from underground sources, the chances of aquifers getting depleted due to excessive pumping are very high as the pumping takes place within small geographical areas creating "cones of depression". This is a phenomenon found in many urban areas around the world including those located in humid climates. Examples are Beijing, Bangkok and Ahmedabad. On the other hand, the tanks and ponds get dried up fast due to heavy diversions. More over, increasing urbanization leads to encroachment of tank catchments for building activities and peri urban agriculture, adversely affecting the inflows from the catchments.
In Kenya, rainfed agriculture is one of the main economic activities for the production of crops. Due to erratic rainfall in most of the arid and semiaridareas, the risk of crop failure is common within small scale farmers who suffer due to lack of water for irrigation. Wherever irrigation is possible, it is necessary to monitor the water quality in order to ensure sustainable crop yields. In dry season, high nutrient enrichment causes eutrophication which is the indication of toxicity in water bodies especially in small dams, canals or slow flowing shallow rivers due to seasonal water level fluctuations and high rate of evaporation in arid and semi-aridareas. Water quality shows current status about the concentration of various solutes at a given place and time . The water quality parameters provide a basis for judging the suitability of water for its designated uses and to improve existing conditions .
Pastoral production system accounts for the livelihood of 50–100 million people in developing countries and 60% of this population lives in more than 21 African countries confined to the most arid and semi-arid regions of the continent (UNDP, 2007). In eastern Africa, Ethiopia has the largest pastoralist population (7–8 millions) representing around 20 ethnic groups (Markakis et al., 2004). Pastoralism and agro-pastoralism are the two major livelihood ways practiced in the region. Animal husbandry in pastoral region is characterized by extensive pastoral production system and seasonal mobility. Camel (Camelus dromedarius) is an important domestic animal species uniquely adapted to the hot and arid environment. The camel is an important animal in Ethiopia because of its adaptation to adverse climatic conditions and shortage of forage and water. It is also an indicator of social prestige and wealth (Bekele, 1999). About 11.5 million of camels are living in the eastern part of Africa (Djibouti, Eritrea, Ethiopia, Somalia and Sudan) representing over 80% of the African and two thirds of the world camel population (Bekele, 1999). In Ethiopia, an estimated 1.7 million camels are present which are mainly distributed in arid and semiaridareas of the country (CSA, 2004).
The groundwater prospect zone in semi-aridareas depends on the spatio-temporal hydrological interaction and that also depends on the characteristics of the local climate, precipitation, surface and landform settings of that area. As precipitation in these area were very less, it may infiltrate directly to ground surface but due to undulation topography of surface precipitation flows as surface runoff through the flow channel. The most of geomorphic and lithology type present in the study had low porosity and permeability. Because of this our study area showed the very little good or very good ground water potential zone. The identification of ground water potential zone in semi-arid region by traditional methodology is not time and cost -effective. For this, geospatial analysis can play important role and identify the ground water potential zones in a cost effective and targeted manner. High potential zones of ground water were found along the lineaments, and along the slope less than 5%. The geomorphic unit like denudational hills and structural hills showed the poor to moderate potential zones in the study area. The low potential zones are located along the slope more than 25% and in the area of denudational hills and structural hills. The implication of geospatial analysis approach in were identification and mapping of ground water prospect zones in semi-arid region is economically viable and it will helps decision maker to sustainable management of groundwater resources in the these area.
spinachristi. Generally the areas are susceptible to desert encroachment, together with the quick fast increase in population in rural areas. The climate parameters, temperature, precipitation, wind velocity, and relative humidity influence soil erosion by wind in semi-arid zones. Decades ago semi-aridareas, as stated by Al-Amin (1999), were relatively free from major human influence and activities accelerate desertification process. The daily needs increase annually. Regarding the semi-aridareas characterized by a meager rain fall, lots of problems will emerge out in the local societies. These problems cover fields like:
runoff in these regions (Pilgrim et al. 988). There are a multitude of different methods for determination of maximum runoff in aridareas; these methods, which use physical and geomorphological characteristics or statistical techniques to achieve their objectives, have been presented by Hames et al. (1998), Jothityangkoon et al. (2001), Foody et al. (2004), Sevinç et al. (2007), Bracken et al. (2008), and McIntyre et al. (2009). Some of these methods calculate the ratio of average annual flooding to annual precipitation of a certain period (Bhatt et al. 2008; Al-Rawas et al. 2010). These methods however require careful calibration and validation by the data pertaining to previously recorded events; so in regions where there are no runoff gauging stations, results of these methods cannot be controlled and verified; in such circumstances, the more proper approach is to use empirical methods to determine the runoff. Limited extent of hydrology-related works on floods of arid and semi-arid regions suggests that those methods that are based on physical characteristics of the catchments cannot yet properly predict the required parameters without extensive calibration, therefore empirical and quasi-empirical methods can provide easier and more accurate solutions for this problem (Bahat et al. 2009; McIntyre et al. 2007).
Flood irrigation is reported from North America, Kenya, the former Soviet Union, occupied Palestine, Aus- tralia, Afghanistan, Pakistan, Yemen, Tunisia, Burkina Faso and India . In North America, Indian tribes have used simple methods of floodwater farming. They have use runoff from sandstone to water alluvial soils in Ari- zona. In pastoral community of Kenya with annual rainfall of less than 200 mm, small patches of sorghum are grown using floodwater. Kovda (1961) reported the use of natural runoff in aridareas of the former USSR called Kair farming whose name is given to cropping on flood terraces (Evidences of flood farming can be found in different parts of Sudan, Morocco, Syria, Jordan and many other countries with similar climatic condition)  . The object of this article is to introduce two major runoff harvesting techniques, Bandsar and Khooshab in central part of Iran.
Arid and semi-aridareas usually have a short term of floods and base flows are very low. Sometimes due to the characteristics of the catchment, several maximums are observed in flood hydrograph, which happens one after another and this reflects the pointed rainfalls in different parts of the catchment. Hence, evaluating the model's performance is very important in these areas. There are different methods to simulate the hydrological processes: pair catchment approach, which only used in small catchments with an area less than 100 km 2
The semi-aridareas of Tanzania are characterized by highly variable rainfall (Yanda et al., 2015). Not only does low and unpredictable rainfall make for uncertainty, but it also lends emphasis to the need for timely access to key resources (e.g. oxen for ploughing, seeds for planting, labor for weeding) for optimum harvest outcomes (Morris et al., 1998). The Gogo agro-pastoral societies in semi-arid Tanzania provide examples of how social protection mechanisms, especially social networks, have helped vulnerable households to cope with various forms of risks like food shortage. These mechanisms involve resource pooling, sharing information, milk, livestock and other resources for households that lost their belongings through different shocks. Social networks among the Gogo in semi-aridareas of Tanzania exist in many forms. They can be categorized on the basis of the membership, whether traditional or modern, and whether formal or informal. These ties are reflected mostly in the ways the agro-pastoralists share labor, gifts, livestock and exchange food items. In fact, the traditional African family is best understood as resulting from a principle of “consanguinity” or blood descent whereby social groups beyond the nuclear family are social units for economic cooperation (Prazak, 2006).
China’s greenhouse is different from that of the developed countries and represents an innovation for year-round vegetable cultivation in China’s arid and semi-arid regions. The term greenhouse identifies the sole dependence on solar power for heating. This technique has been extensively applied in China’s cold northern areas between latitudes 30°–44°N. Many vegetables can be suc- cessfully cultured not only in spring and summer but also in winter in China’s cold areas without need for artificial heating. Area of greenhouse in China was said to have reached 380 000 ha (Zhang and Li 2006). Especially, many greenhouses in the hilly semi-arid area were built on the slope land, which can not only control the soil erosion but also enhance the slope land productivity (Gao and Liu 2004). China’s area of such cultivation has become the largest in the world. The average per capital consumption of vegetable supplied by greenhouse is over 27.6% of total vegetable consumption. However, most semi-arid regions of North China are suffering from a shortage of water, which hinders the development of greenhouses there. Water shortage in winter is still a limiting factor in using greenhouses.
The experiments last for two consecutive seasons, using the 1-factor completely randomize design (tillage factor). The experiment total number of runs was six; each run has a size of 13 x 70 m. Furrow and chisel tillage as in-situ rainwater harvesting techniques (IRWHT) were implemented against control plots at three different climatic zones: arid (Wadmedani station, Gezira state), semi-arid (Sennar station, Sennar state) and semi-humid (Abunaama station, Sennar state). The locations of the three sites are shown in Figure 1. For each IRWHT, three replicates were made. In order to avoid effects of water stagnation, the seeds were placed a little bit higher than the beds of the furrows by a conventional planting method (traditionally known as Saluka) with 0.2 - 0.3 m between holes (3 - 4 seeds per hole). However, for the control treatment plant distances of 0.7 – 0.8 m between holes were used (the widespread practice adopted by local farmers). Dykes at the plots ends were constructed manually in order to collect the in situ surface runoff, i.e. maximizing the infiltrated rainwater volume so as to increase the soil moisture content in the root zone. The experimental sites belong to the central clay plain, where the soil is vertisols (Elias et al., 2001; Blokhuis, 1993) with a clay percent of 52- 58%. On one hand the soils are characterized by moderate to poor mineral fertility due to low content of nitrogen, available phosphorus, and sometimes potassium (FAO, 2006). In spite of these deficiencies, rainfed farmers, whether in traditional or mechanized sector, do not use fertilizers in order to reduce the cost, i.e. rainfed farmers, especially traditional farmers, receive very low percent of all formal agricultural credit, besides that they receive few support services such as research and extension (FAO, 2006). On the other hand, due to relatively higher cation exchange capacity and percentage base saturation values, these soils have greater ability to retain added nutrients and reduced tendency to lose by leaching (FAO, 2006).
It is estimated that about 21% of communicable diseases in India are water related (Brandon et al. 1995). The water quality issue is now being recognized in India as a major crisis. In most parts of the country, the water supplied through groundwater is beset with problems of quality (CGWB Report 2002).The over dependency on groundwater has led to 66 million people in 22 states being at risk due to excessive fluoride, and around 10 million at risk due to arsenic in six states (Husain et al. 2003, 2013, Ghosh 2007). In addition, there are problems due to excessive salinity, iron, nitrates and others (Desai 1990). Around 195 813 inhabitants are affected by poor water quality due to chemical parameters (CPCB 1999). It has been estimated that once pollution enters the subsurface environment it may remain concealed for many years, becoming dispersed over wide areas of groundwater aquifers and rendering groundwater supplies unsuitable for consumption and other uses. The rate of depletion of groundwater levels and deterioration of groundwater quality is of immediate concern in rural areas of the country. The increased dependency on groundwater has made water conservation the top priority in water management studies.