Water-related limits to growth for agriculture in Iran

Globally, agriculture is the primary water consumption sector. This study used water footprint (WF) as a bottom-up tool and satellite imagery as a top-down tool to estimate the internal water use (WU) in the agricultural sector in an innovative way to show the effects of water-intensive use in agriculture in an arid country. The WF of Iran has been quantified for 19 main crops and for related agricultural products exported from Iran to partner countries. Using a bottom-up approach, Iran's total yearly agriculture net water consumption is estimated to be 42.43 billion cubic meters (BCM) per year. Out of 42.43 BCM total net internal water use, only 1.61 BCM is virtual-water export related to these 19 products, and the remaining 40.82 BCM is for internal use. Our results using satellite imagery show that in case of using all possible lands for agriculture, it would require 77.4 BCM. However, not all these lands are within human reach, and the maximum available water is way lower than this amount. Using satellite imagery, the total evaporation from agricultural lands shows 55.27 BCM for 2020, which agrees with national reports during 2005-2014. This study shows that agricultural water consumption tends to use internal water resources at a maximum level for export and national use, significantly impacting renewable and non-renewable water resource availability, especially in groundwater.

The edge of the petri dish for a nation: Water resources carrying capacity assessment for Iran

Different methods have been proposed in population dynamics to estimate carrying capacity (K). This study estimates K for Iran, using three novel methods by integrating land and water limits into assessments based on Human Appropriated Net Primary Production (HANPP). The first method uses land suitability as the limiting resource. It gives theoretical estimates for K. The second method which is based on the first method, uses land suitability and water resources availability as limiting resources assuming highly efficient agriculture, also resulting in theoretical estimates for K. The third method is based on the second method assuming a lower, more realistic agricultural efficiency. The third therefore results in more realistic estimates. Four spatial hydrological scale levels were considered to estimate food production. Also, nine scenarios were defined: a reference one reflecting the current situation, five others for the first method, two for the second method, and finally, one scenario for the third method. Results show severe limitations on food production by the availability of suitable land, water availability, and crop productivity for agriculture. We estimated theoretical values for K using land and water limiting resources separately. Two realistic scenarios considering realistic agricultural productivity and water use at national and local levels were assessed, resulting in 35.5 and 20 million people, respectively. These are alarming values compared to the current population of Iran (84 million). Moreover, our conservative estimations are still higher than any assessment when considering social, economic, or political barriers. This research provides a systematic analysis of carrying capacity in Iran, showing the importance of food import on Iranians' lives, relevant to land, water, and food policies.

Ecuadorian water funds' use of scale-sensitive strategies to stay on course in forest and landscape restoration governance

Water funds are task-specific organisations that conserve and restore watersheds. The funds provide sustained finance and a collaborative space for actors at different levels to improve the water regulation functions of upstream ecosystems, safeguard water quality, and establish ecological connectivity with the aim of ensuring downstream water quantity and quality. However, while implementing conservation and restoration efforts at local level, water funds encounter scale challenges, consisting of mismatches between the ecological and the governance scale and misalignment between governance levels. This study's aim is to identify and unravel both the scale challenges with which two Ecuadorian water funds (FONAG and FORAGUA) were confronted and the scale-sensitive governance strategies that they planned and deployed to overcome them. We collected data through a document review, 48 semi-structured interviews, and participatory observation, and used content analysis methods to analyse the interview transcripts. Consequently, at both funds, we identified a blind spot towards rural livelihood realities, a temporal mismatch between short-term election cycles and long-term restoration timelines, and a spatial mismatch between the reach of restoration efforts and degradation processes. At FORAGUA, we also identified heterogeneity across levels regarding the purpose of restoration, with different spatial implications. We identified a total of 12 tailored strategies that the two water funds deployed or aim to deploy in reaction to these challenges in an attempt to re-create fit with ecological processes and alignment with other governance levels. Some of these strategies caused new scale challenges to emerge. By observing and acting on emerging scale challenges, water funds try to stay on course to achieve restoration objectives. We conclude that the water funds, which are governance arrangements designed to create spatial and temporal fit with ecological processes, have to continuously adapt their governance strategies to maintain cross-scale fit and cross-level alignment.

Hybrid power generation for increasing water and energy securities during drought: Exploring local and regional effects in a semi-arid basin

Reservoirs of hydropower plants (HPP) can amend water, energy, and food security in semi-arid regions. However, during severe droughts, the priority of energy demand leads to critical conditions of water availability. To reduce water use for energy, one possible measure is the adoption of solar power, an abundant energy source in semi-arid regions. This study assessed the influence of adding floating photovoltaic power (PV) in the large-scale reservoir of Sobradinho HPP, located in the São Francisco River (SFR), in Brazil, from 2009 to 2018. The simulated scenarios varied the installed PV power capacity from 50 to 1000 MW. For each scenario, water allocation was modified based on the solar-hydro equivalence that restrained the historical outflow of Sobradinho to maintain water in the reservoir. Besides, a diverse operation rule for the reservoirs in cascade of SFR was adopted to avoid ecological impacts of low streamflow. The scenarios were assessed in water security, solar-hydro electricity output, capacity factor of the powerplant, water and energy losses by evaporation and spilled water. Results show that a PV system starting from 250 MW was necessary to improve water security during the severe drought, reserving 0.7-2.3 of the annual water demand. In addition, the capacity factor was optimized from 29% to 34-47%. However, as the HPPs installed at SFR work as one system, the constrain of the river flow reduced the hydroelectricity by 4.4% for 750 MW. We concluded that PV significantly influenced water security and ecological conditions of SFR, with benefits in the range of 250-750 MW. The research provides assessment on substituting hydro for solar power on the operation of reservoirs in cascade and identifies the correlated benefits in social and ecological aspects. This information can support decisions of water and energy supply system operators and public policies focused on integrated resources management in semi-arid regions.