Climate change and groundwater resources availability in the Great Limpopo National Park (Mozambique): the current state of knowledge

This work outlines a comprehensive study of groundwater resources supply in Mozambique’s Great Limpopo National Park buffer zone in Southern Africa. To protect biological diversity and the water resources supply of dispersed communities of the buffer zone is a crucial problem to fix people in the region and, in the meantime, to boost the development of the Limpopo National Park. This work shows the current state of knowledge about this topic and try to point out some suggestions on technical solutions. Some previous studies concluded that two different main factors make a complex water supply in this area: (i) the rainwater distribution, it is hard to transform the rainwater into groundwater resources available for exploitation, and (ii) the common groundwater resources, rich in elements such as Boron (B), Mercury (Hg), Uranium (U), Zinc (Zn) and Lead (Pb). The occurrence of these elements is linked to the presence of groundwater with long residence times, unsafe for people’s health. The methodological approach adopted has been to assess the potential infiltration, applying the inverse hydrogeological budget technique, starting from the main outcropping geological units, in the study area. Due to the lack of meteorological data referred to Limpopo National Park, the gauge stations located in the Kruger National Park during the last 64 years have been, on the whole, considered. The target of the study has been to assess the trend of meteorological data and understand how precipitations could affect groundwater recharge and their availability. Without a strategy of biodiversity conservation and sustainable water resources management, they cannot be reached and guaranteed healthy conditions for local dispersed communities. A hydrogeoethical responsible approach is essential to protect biological diversity and hydrosocial cycle framework with integrative ecosystem services and nature-based solutions.

Community-owned rural water supplies in Galicia (Spain): supporting role in the groundwater self-management

The community-owned rural water supplies in the rural areas of Galicia developed spontaneously in response to the historical shortcomings of local administrations, which are a clear example of commons management strategies. They have developed a water self-management model integrated into a complex network of actors. More than one-quarter of the total population rely on these systems. However, a large part of supplied water does not comply with the sanitary standards due to deficiencies in the system’s design, operation, and maintenance and the water catchment protection. Furthermore, the owners face difficulties complying with basic legal requirements due to the complexity of the regulatory framework and the lack of training of the water board members. COXAPO (‘Comunidad Xeral de Augas de Galicia’), an association of 150 community-owned water supplies, advises, trains, and supports the water boards for the legal, administrative, economic, and technical systems management. As a result, it gets the systems legally compliant concerning the institutional management and quality of supplied water. The success of this network governance recommends a role to the administration in promoting the networking of water boards by supporting the existing water supply associations and encouraging their constitution or provisioning equivalent services in regions where they do not exist.

Archaeoseismological study of the Cherichira aqueduct bridge, Kairouan, Tunisia

In the past, several destructive earthquakes have occurred in the North African Atlas Mountain ranges located along the Africa–Eurasia plate boundary. Although the region is rich with impressive archaeological sites, including those in modern Tunisia, few comprehensive archaeoseismological studies have been conducted. Historic sources account at least three damaging earthquakes in the Kairouan area in central Tunisia between AD 859 and 1041. Little is known about which faults triggered these earthquakes or the size of these events. The water supply of the city of Kairouan depended on a 32-km-long aqueduct with a large bridge (now partially collapsed) at the confluence of the de Mouta and Cherichira rivers. The original bridge of Roman construction was retrofitted twice during the Aghlabid period (AD 800–903) and probably in AD 995 during the Fatimid period. The ruined section of the bridge shows damage which might be related to the AD 859 earthquake shaking. Here, we present a detailed study of the history, the status and the damage of the Cherichira aqueduct bridge using previous historic accounts and written works, a 3D laser scan model, local geological and seismological characteristics, and include results of radiocarbon dating and a timeline of events. In addition to earthquake ground motions, we consider severe flash floods on the bridge as a potential cause of the damage. We estimate the severity of such flash floods and develop a model with 18 earthquake scenarios on local reverse and strike-slip faults with magnitudes between MW 6.1 and 7.2. While a few damage patterns might be indicative of flooding, most damage can be attributed to earthquakes. It is highly probable that the earthquake in AD 859 caused enough damage to the Aghlabid bridge to render it dysfunctional; however, to resolve the question of whether another earthquake in AD 911 or 1041 caused the complete destruction of the previously retrofitted aqueduct by the Fatimids requires dating of additional sections of the bridge.