A GIS-based methodology to quantitatively define an Adjacent Protected Area in a shallow karst cavity: The case of Altamira cave

Different types of land use are usually present in the areas adjacent to many shallow karst cavities. Over time, the increasing amount of potentially harmful matter and energy, of mainly anthropic origin or influence, that reaches the interior of a shallow karst cavity can modify the hypogeal ecosystem and increase the risk of damage to the Palaeolithic rock art often preserved within the cavity. This study proposes a new Protected Area status based on the geological processes that control these matter and energy fluxes into the Altamira cave karst system. Analysis of the geological characteristics of the shallow karst system shows that direct and lateral infiltration, internal water circulation, ventilation, gas exchange and transmission of vibrations are the processes that control these matter and energy fluxes into the cave. This study applies a comprehensive methodological approach based on Geographic Information Systems (GIS) to establish the area of influence of each transfer process. The stratigraphic and structural characteristics of the interior of the cave were determined using 3D Laser Scanning topography combined with classical field work, data gathering, cartography and a porosity–permeability analysis of host rock samples. As a result, it was possible to determine the hydrogeological behavior of the cave. In addition, by mapping and modeling the surface parameters it was possible to identify the main features restricting hydrological behavior and hence direct and lateral infiltration into the cave. These surface parameters included the shape of the drainage network and a geomorphological and structural characterization via digital terrain models. Geological and geomorphological maps and models integrated into the GIS environment defined the areas involved in gas exchange and ventilation processes. Likewise, areas that could potentially transmit vibrations directly into the cave were identified. This study shows that it is possible to define a Protected Area by quantifying the area of influence related to each transfer process. The combined maximum area of influence of all the processes will result in the new Protected Area. This area will thus encompass all the processes that account for most of the matter and energy carried into the cave and will fulfill the criteria used to define the Protected Area. This methodology is based on the spatial quantification of processes and entities of geological origin and can therefore be applied to any shallow karst system that requires protection.

Effectiveness of Low-Cost Planting Techniques for Improving Water Availability to Olea europaea Seedlings in Degraded Drylands

Reforestation projects in semiarid lands often yield poor results. Water scarcity, poor soil fertility, and structure strongly limit the survival and growth of planted seedlings in these areas. At two experimental semiarid sites, we evaluated a variety of low-cost planting techniques in order to increase water availability to plants. Treatments included various combinations of traditional planting holes; water-harvesting microcatchments; stone or plastic mulches; small waterproof sheets to increase water harvesting; dry wells; buried clay pots; and deep irrigation. Some of these treatments were also combined with addition of composted biosolids. Waterproof sheets significantly enhanced water harvesting (43%) and soil moisture in the planting hole (40%), especially for low-intensity rainfall events. Treatment effects on the survival and growth of Olea europaea seedlings varied between experimental sites. At the most water-limited site, clay pots, and dry wells improved seedling survival, while no treatment enhanced seedling growth. At the least water-stressed site, the application of composted sludge significantly improved seedling growth. We conclude that nutrient-mediated stress is subordinate to water stress in arid and semiarid environments, and we suggest modifications on the microsite scale to address these limiting conditions in Mediterranean drylands.

Steel Pedestrian Bridge to Protect a Unique Tree

This paper describes the “Variation Guggenheim 3: Mirador de la palmera” project, situated in Daya Vieja (Alicante-Spain). This structure is inspired by the Guggenheim museum of New York and is designed to protect a land-mark palm-tree from wind loads. This six – trunk palm tree was declared monument by the Valencian government in 2012. The structure that now protect it appears to fly around de palm tree creating a helicoidally skywalk made of steel, while retrofitting the lateral trunks of the tree to protect them from collapse. An 18 m. long straight beam starts on the top of this helix, and stretches towards a lookout point that offers a view of the whole village and its surroundings. The reduction of the visual impact of the structure on the tree was a major aim for the project design. The structural elements are as slender as possible to avoid the visual obstruction of tree. They are painted white, while the walkway steel corrugated plate is painted green in order to highlight its neat shape among the blur created by the apparent mess of bars of the supporting structure. The two main piles of this pedestrian bridge were designed in steel and geometrically resemble trees. A Ground Penetrating Radar analysis was performed to detect the palm root location and to decide the best foundation system. Slender cast in-situ steel-concrete micropiles along with a concrete pile-cap, raised some centimeters above the ground level, were used to reduce the damage to the roots. The projected pile-cap is a slender, continuous, circular ring; which geometry resembles a concrete bench. This structure has been a finalist in the Architecture Awards for the 2010-2014 best construction projects, held by the Diputación de Alicante.

Engineer Leandro Badarán’s project to safeguard the fortresses of Alicante in 1794

After the construction of the San Carlos bastion in Alicante in the final decade of the seventeenth century, and the great trench which the English built around the district of San Francisco during their years of dominance in the War of Succession, the waters of the San Blas gully caused serious damage to these fortifications of the city and to the trade buildings of the port. In 1772, the diversion canal was built. It was designed to divert the riverbed of the gully and send the waters directly to the sea. The project had been initially designed by the Engineer General, Jorge Próspero de Verboom in 1721. This unique work of engineering had some defects, principally in the breakwater which prevented the waters from flowing down the former river course. On several occasions, the water returned to its original riverbed due to the weakness of the breakwater, the narrowness of the channel’s bed and its lack of regularisation, causing serious damage to the bastion, the Babel-facing façade, the traders’ warehouses and other buildings. This study describes the project that the military engineer Leandro Badarán carried out in 1794 in order to technically improve this canal and examines his report on the state of the fortifications. Similar works built in Spain are also explained. It also analyses the repeated disputes between the war department and the port throughout these years over finding a technical solution to the problem.