IRELAND’S RIVER NETWORKS TOLKA RIVER AND CATCHMENT THESIS TITLE SOURCE: Dunshaughlin, Co Meath GIVING RIGHTS TO THE RIVER TOLKA 57km TOTAL LENGTH DUBLIN MEATH CATCHMENT AREA 14,150ha 140m DROP OVER THE COURSE MOUTH: THESIS STATEMENT Dublin Bay, Co Dublin Landscape architects must address the impaired and threatened Irish water channels and bridge the link for a much needed urban-ecological framework LAND TOPOGRAPHY LAND USES Starting upstream towards the source of the River Tolka, the river is stream like Both urban and rural stages of the rivers course contributes to the degraded state of the making it more vulnerable to the harmful impacts occurring in the surrounding river Tolka. It is important to look at the harmful impacts as a whole and not blame one over environments. the other. Agricultural activity primarily takes place upstream where the river is extremely vulnerable. URBAN GREEN A B C MOTIVATION D The River Tolka over the past two centuries has not SETTLEMENTS changed drastically in its course but its health has E deteriorated significantly. Once a river polluted with fish is now polluted with waste due to urban activity, from F fertilizers of agricultural land leaching in, to direct waste pumping into the watercourse. The conditions of the river Small streams are highly vulnerable to pollution and other human induced are not meeting the EU standards, despite being brought disturbances because of their high connectivity with adjacent land. to court over the matter where the Irish Water pleaded Threats: guilty to offences under the Water Waste Discharge. The Low dilution capacity river had a major fish kill in 2018, European Commission Vulnerability to channel modification TILLAGE gave Ireland repeated warnings and little resolution has Vulnerability to environmental change been made for these ongoing issues. Small Streams represent 77% of the length of the Irish river network, they provide us with many benefits, Fish species used to thrive in the shallow waters upstream of the Tolka river, particularly for trout and salmon. The juveniles of trout can spend several years in these streams before migrating downstream where they become the catchable fish. GRAZING A B C D E F SCALE 1:75000 CONDITIONS ALONG THE RIVER Many factors have contributed to The River Tolkas degraded state both upstream and downstream. Identified are seven of the conditions that have the greatest on going adverse impacts on the course’s health. * * * Conditions of focus SCALE 1:25000 GIVING RIGHTS TO THE RIVER TOLKA CONCEPT LAND CUT OFFS Land cut offs are the small fragments of land that stand alone due to the river intersecting a field into two.These fragments of interest are primarily agricultural land that is under private ownerships. The river begins it’s course very small almost stream like making it very vulnerable to STRATEGY 1 the farming activities. By giving small slots of land back to the river attempts to decrease the harsh impacts to its course and health. ‘ISLANDS IN THE RIVER’ STRATEGY LAND FRAGMENTS LAND OWNERSHIP Creating a series of public open spaces on the fragments of land that have been formed due to the river intersecting a field into two. These fragments fall below a threshold in size and each fragment is developed based of its individual surroundings. Opening these fragments to the public will eliminate farming activity at the river’s edge on one side and will simultaneously resolve other conditions identified along the river Tolka’s course. AREA 2630m² Area of intensive 8. farming, river is a small stream and vulnerable at this upper stage of its course . SCALE 1:35000 7. Harsh farming at AREA 20847m² the banks of the FRAGMENTS LOCATION & LANDHOLDING river with little evidence of aquatic formation. 8 7 6 5 4 3 2 1 Area has an AREA 3761m² 6. increased velocity rate, floodplain will prevent flooding further downstream. SCALE 1:15000 SYSTEMATICALLY RESTORING THE FRAGMENTS BACK TO THE RIVER AREA 16395m² 5.Some existing herbaceous species, potential to expand and link between the aquatic and terrestrial ecosystems. 4. Access point AREA 4374m² from the main road and a local existing community promotes the appreciation and PUBLIC INTERACTION interaction of the New entrances are proposed to open this river Tolka. ‘island’ connecting into existing communities, many of which are deficient in access to nature and the river. It will be provide and viewing platform, allowing visitors to understand their place in this distinctive landscape. Proposing opening this ‘island’ to the public, which was formerly part of grazing land opposite, will eliminate farming at the river’s edge on one side and the introduction of a buffer zone between the grazing land and the river will reduce the harmful impact on the rivers health. The open view to the agricultural land will also ensure that the farmers are adhering to the regulations set in place. 3.A linear dock just past the toll allows AREA 10489m² for drivers to have a safe place to pull in and have lunch, and allow for fishing as it is not too close to the source of the river, it is now established. WILDLIFE HUB Acquiring charm from the trees that grow in the surrounding environment and the natural growth on this little ‘island’ when left fallow, it becomes a nature reserve for large numbers of birds, flora and fauna. It creates a ‘green core’ of a naturalised landscape. Existing site habitats will be enhanced and extended to further enrich and diversify, increasing habitats for protected species and attracting a wide variety of new species to the site. AREA 3047m² This will improve the rivers health as there is no farming activity on one side of the river 2 Area prone to flood and it will increase the biodiversity network . in high rainfall, along the river as it flows downstream. plentyful trees and the proposal to increase, can form a retention forrest to reduce flooding and manage water run-off. AREA 3057m² 1.Local communities and industrial workers have easy access to this fragment of land creating the link between the public and the river while reducing agricultural harm. GIVING RIGHTS TO THE RIVER TOLKA CONCEPT LACK OF PUBLIC ACCESSIBILITY The river tolka flows past Dunboyne town and Clonee town, however the is very little acknoledgement or interaction with the river. Rivers have many benefits for people such as recreational use, education about nature, healthcare and creating an identity. Although the two town have their individual identities by sharing a common space in between them will create a STRATEGY 2 stronger community bringing many more benefits to the residents of Dunboyne and Clonee. ‘TWO TOWNS TRIBUTARY’ WATER SYSTEM COLLECT CLEAN DISCHARGE STRATEGY In order for the public to appreciate and protect the River Tolka they must see and interact with it. The strategy was to use the river as a link between Dunboyne and Clonee while simultaneously benefitting the river and the residents.The route is dictated by both the existing tributary and the existing field boundaries. The existing stormwater runoff tributary route from Dunboyne has transformed its course into a filtration system before joining with the river Tolka. This strategy creates a necklace of ponds following the field patterns. The ground level walkway allows people to have close contact with nature. Some areas can only be used when there is low to moderate rainfall, this encourages the public have an awareness of their environmental surroundings. The raised walkway can be used during periods of heavy rainfall to allow the lower course of the walkway to flood, this is a positive environmental amenity in the city as it prevents flooding occurring further downstream. SCALE 1:7500 LET IT FLOOD, LET IT GROW In times of heavy rainfall this proposed floodplain alleviates the risks of 0-15 YEARS The water sits in depletions in the flooding further downstream. The floodplain which was once grazing Early stages of the strategic land in times of low/ moderate rainfall land has grooves in its surface, resulting in water sitting during times of floodplain is primarily planting that little rainfall. is related to the existing biomass and habiats 15-30 YEARS As the development matures over time vegetation growth is stimulated due to the fallow farm land and exposure to the elements, spreading of seed bank and species establishing Land floods when there is high habitat communities and diverse precipitation and river bursts ecological matrix’s SCALE 1:100.