Wetlands Protection and Creation (Kigali edition)

(In limba Romana, mai jos)

wetland kigaliHappy world wetlands day! ..although 64% of the world’s wetlands have disappeared since 1900 (according to UNEP&Ramsar Convention on Wetlands).

This article presents an example of what work landscape architects can do, and should do.

Wetlands have high potential for connecting the natural biophysical system and human settlements in developing alternatives for a city adapted to meet to climate change challenges as well as increasing urbanization. One of the projects I am most happy with has approached the urban expansion and development of Kigali City, where on the one hand, the wetland ecology is losing field in front of man-made development and on the other hand, the human settlements on the border of the wetland are victim of floods and landslide.

masterplan kigali

With informal urban expansion, the wetland is threatened to be occupied by concrete. The ecosystems formed with the presence of water are divided and disconnected, threatened by all that involves movement, exchange and goods consumption; continuous expansion of human influence (build environment, greenhouse gas emissions, un-proper urban services), but also threatened  by factors directly or indirectly caused by climate change (temperature, drought or high amount of rainwater).

The urban wetland in Kigali captures, retains and drains the water in Nyabarongo River, a Ramsar site. One of the characteristics of a Ramsar Site is that the wetland contains species that are protected from any pollution that is threat to modify their genetic composition.

research ligic wetland kigali

Design Principles

Buffer zone. Adapted to the constructed profile of the surroundings, the buffer zones have the main function of connecting the wetland with a larger spatial context (neighborhood/ city level). A buffer zone of an reserve commonly allows active human use as agriculture practices or orchards, and it also used for activities as education, recreation and ecotourism.

buffer zone

buffer zone pic

Border line. The abiotic layer of the wetland can be highlighted on topography with a natural border represented by steep slopes. A limitation of access is required to separate the human access areas from areas not assigned for human intervention. The borders of the wetland park are customized to the neighboring setting as well as the specific ecological activities.

Retaining water. The annual runoff can be reduced from 76,65mm to 3mm if the swamp will increase its catchment area with 1-10 % (calculation based on Patrick Denny, 1985). In the specific case of Kigali, the water ponds have to be designed in a way to allow people collecting water for domestic use.

retaining water kigali

Wetland Production. The floodplain consist of two specific areas the aquatic part with the submerging ecosystems and the terrestrial one – seasonally flooded. Both of the areas have high value in capturing the greenhouse gas emissions. The wetland can have a considerable production of fodder crops where plants up to 2 m (such as Phragmatites australis and Echinochloa stagina), an important nutritional base for animal consumption but also raw matter for building material and other manufactured goods. Considering the temporal floods and the various time frame of evaporation, the aquatic and terrestrial zones can complement each other in matter of production and regulation of microclimate.

Erosion and landslide control. The steep slopes along the valley are a risk for both human settlements and for activities taking place around. In order to prevent land sliding, the terrain can be shaped in order to provide space for agricultural practices, social activities, water drainage and cleaning features. Using local materials the landscape is reshaped not only through a functional design but it as well promoting the authenticity of local installations.

prospected layout kigali

Wetlands, my dearest passion. When I was a student and needed to take a break I`d look on Googlearth of beautiful shapes of nature. You Earth, so beautifully curved!

Russia 70.6799246, 131

Russia 71.0979013, 132

 

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Crearea si Protectia Zonelor Umede (Editia Kigali)

wetland kigali

Astazi este ziua zonelor umede, desi 64% din ele au disparut din 1900 (potrivit UNEP si Conventiei Zonelor Umede Ramsar).

Acest articol este un exemplu de munca pe care arhitectii peisagisti pot sa o faca, si ar trebui sa o faca.

Zonele umede au un potential ridicat de a conecta sistemul biofizic natural cu asezarile umane, in a crea alternative de dezvoltare pentru un oras adaptat la schimbari climatice si continua urbanizare (extindere). Unul dintre proietele proprii care ma bucura cel mai tare a avut ca subiect extinderea urbana si dezvoltarea orasului Kigali, unde pe de-o parte ecologia zonelor umede pierde teren in fata dezvoltarii umane, iar pe de alta parte, asezarile umane care marginesc zonele umede sunt victim ale inundatiilor si alunecarilor de teren.

masterplan kigali

Cu extinderea asezarilor informale, zonele umede sunt in pericol de a fi acoperite de constructii. Ecosistemele formate cu prezenta apei sunt intrerupte si deconectate, amenintate de tot ceea ce inseamna miscare, schimburi de consum de produse, continua extindere a influentei umane (mediul construit, emisii de gaze cu effect de sera, servicii urbane ne-adecvate), dar si amenintate de impactul direct sau indirect al schimbarilor climatice (schimbari abrupte de temperatura, seceta, sau ploi torentiale in  volum mare).

Zonele umede in orasul Kigali captureaza, retine si ditectioneaza apa in raul Nyabarongo, care este sit Ramsar. Una dintre caracteristicile unui sit Ramsar este ca situl sa contina specii care sunt protejate de orice poluare care le ameninta compozitia genetica.

research ligic wetland kigali

Principii de design.

Zona de tranzitie. Adaptata la profilul constriut al zonelor din apropiere, zona de tranzitie are principala functiune de a conecta zonele umede cu zona urbana din apropiere (la nivel de cartier, sau la nivel de oras). O zona de tranzitie catre o zona protejata permite activitati umane precum practicarea agriculturii sau livezi, insa poate fi folosita si in activitati educationale, recreatie si turism.

buffer zone

buffer zone pic

Delimitare. Volumul de apa pluviala poate fi redus cu 76,65mm pana la 3mm daca zona umeda are zona de retinere a apei marita cu 1-10% (calcul bazat pe formula data de Patrick Deny, 1985). In cazul orasului Kigali, bazinele de reinere a apei trebuie sa permita oamenilor colectarea apei pentru consum casnic.

Productivitatea zonelor umede. Zonele umede contin doua parti: partea acvatica cu ecosistemele proprii, si partea terestra, care este inundata sezonier. Ambele parti au o mare importanta in caprurarea gazelor cu effect de sera. Aceasta zona poate produce furaje din plante care ating 2 metrii inaltime (Phragmatites australis, Echinochloa stagina), ceea ce ofera o baza de nutritive pentru animale; dar si posibil material de constructie si materie prima pentru bunuri manufacturate. Avand in vedere variatia perioadelor ploioase si secetoase, partile terestra si acvatica se completeaza in ceea ce priveste productia vegetala si reglarea microclimatului.

retaining water kigali

Eroziunea si controlul alunecarilor de teren. Pantele abrupte in apropierea zonelor umede sunt un risc pentru asezarile umade dar si pentru activitatile care au loc in apropierea lor. Pentru a prevenii alunecarile de teren, terenul poate fi redefinit pentru a adopta cultivatrea terenului, activitati sociale sau elemente pentru scurgerea si curatarea apei. Folosind material locale, peisajul poate fi redefinit nu numai catre un design functional dar si promovand autenticitatea instalatiilor artistice locale.

prospected layout kigali

Zonele umede, pasiunea mea draga. Cand eram student si aveam nevoie de o pauza, ma uitam pe Googlemaps admirand frumoasele forme ale naturii. Pamant, asa frumos te-ai ondulat!

Russia 70.6799246, 131

Russia 71.0979013, 132

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