Wen Zhong

capture fresh water on the island

Landscape Architecture - MLA

Edinburgh School of Architecture and Landscape Architecture (ESALA)

zhong_wen1234@163.com

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The freshwater dilemma

Graciosa Island is located in the northern part of the central group of the Azores. This island is currently experiencing seawater intrusion into the groundwater aquifer, which, if not improved, will pose a significant threat to the island's ecosystem and the health of its inhabitants. There are two reasons for this situation to arise. The first reason is That there are no lakes or rivers on the island, the islanders rely heavily on groundwater for their daily water. Excessive groundwater extraction leads to aquifers can not being recharged in time, which eventually led to seawater intrusion.

At the same time, human deforestation increased pastureland on the islands. Because of that, the gradual replacement of deep-rooted plant communities with shallow-rooted ones has increased the probability of surface water loss and reduced the surface runoff naturally recharging the aquifers.

Site location

The site of this project is located in the foothills of the central mountainous region. Because of the mountains, this area has high precipitation. The vegetation root system here is predominantly shallow-rooted, but there has a continuous patch of forest. Through software simulations, we have obtained the possible locations of seasonal water flow channels.

Proposal

For this graduation project, I wanted to try to improve the current difficulties of surface water infiltration on the island and to improve the intrusion of seawater into the aquifer. At the same time, I wanted to turn the process of tracing water and retaining rainwater within the site into a story that visitors could read. Turning the plight of the freshwater resources that exist only on the Graciosa island of the archipelago into a design theme for the landscape nodes, and in doing so, helping the island to attract more tourism resources than the current over-reliance on grazing.

There are two main strategies in this project. Strategy 1 is a landscape node design strategy that combines the capture of seasonal water flow. Strategy 2 is a groundwater recharge strategy based on the restoration of deep-rooted vegetation communities and the interception of rainwater.

Strategy 1

For the strategy, This project has selected 4 main areas as design areas and I will use different design solutions to respond to the theme of capturing water flow.

Entrance area

The entrance area connects to the island road system, and visitors can gather in this area. For this entrance area. The red road is paved with Lapilli, and I wanted to break up the original farmland texture of the site with this red road.

Water blcok

The water clock is the second landscape node that visitors will reach upon entering the site. This node will be built entirely in conjunction with the water catchment line. It has 2 layers of water of different heights, which will create an artificial waterfall here when the rainfall is enough in the rainy season. The waterfall hitting the stone slabs will Make a sound and tell people that the rainy season is coming. this is a clock that is entirely controlled by nature. And the end of the water clock is an artificial wetland to catch the water from the structure.

Water belt

The water belt was inspired by the stone pond in Japanese gardens. I wanted to use the basalt of the island to mark the possible locations of seasonal water flow. The use of stone, a material that will not change for a long time, to capture water, an extremely changeable substance, gives a sense of the freshwater flow that once walked the island. In the meantime around the water belt, I will plant a selection of plants that have been found on the island witch will flower in spring. Spring is the end of the rainy season on Graciosa. At the end of the rainy season, the water belt will be full of flowers. It echoes the water clock, these two structures, one representing the arrival and one marking the departure of the rainy season. For the islanders, the dry season can be unsettling, and I wanted to use flowers as a form to show the islanders that is just a natural process; whether it is dry or rainy, it is life.

Water temple

The water temple is located at the highest point of the site. As the last node in strategy1, I want to elevate the story of water in this area. This is a building that stands on a high mountain and collects rainwater to create a waterfall on the wall that reflects the sky. From here, one can see the true source of fresh water on this island, is the sky. This water then falls into the forest below the building, irrigating the growth of the forest. This process is Symbolic of how life first began on this island.

70 years later

Strategy 2

The groundwater recharge strategy is based on deep-rooted vegetation community restoration and rainwater interception. This is an experimental ecological strategy. It incorporates the different topographical conditions of the areas within the site.

Interceptor ditch

The interceptor ditch is a system of above-ground ditches, underground water storage soakaway and native plant communities. This structure will be settled in the pasture area near the entrance. The above-ground ditch allows the animals to drink, and the underground section, which stores the water in the soakaway. The rainwater is slowly infiltrated into the ground through the soakaway. Part of it will supply the survival of the plant witch planted in the ditch during the low rainfall season. This system not only collects rainwater but also helps the recovery of deep-rooted vegetation communities.

Catchment planting pond

Catchment planting pond adjacent to the borderline between forest and grassland. It is based on the restoration and expansion capacity of the forest system itself, with the help of artificial facilities for rainwater retention and the restoration of deep-rooted vegetation communities, to improve the natural rainwater infiltration process within the site. In times of drought, these buried water storage planters increase the resilience of the system and its ability to recover itself.

Temporary pond

The last temporary pond area is located in the canyon area at the end of the site. This area brings together the water flow from the mountain and the foot of the mountain. This is a place where water is plentiful. Without human intervention, this rainwater would have followed the catchment line and gone to the sea. Temporary ponds system are provided here to capture rainwater and recharge the ground through diffuse irrigation.