Xinyu Xiao. Re-Embedding Settlement in a Reinforced Open Canopy Landscape

RE-EMBEDDING SETTLEMENT IN A REINFORCED OPEN CANOPY LANDSCAPE

Xinyu Xiao 2017-2018 K.U.Leuven, Master of Urbanism and Strategic Planning

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RE-EMBEDDING SETTLEMENT IN A REINFORCED OPEN CANOPY LANDSCAPE

Xinyu Xiao

Promotor: Bruno De Meulder Co-promotor: Wim Wambecq

MORE INFO? MAHS / MAUSP / EMU Master Programs Department of Architecture, K.U.Leuven Kasteelpark Arenberg 1, B-3001 Heverlee, Belgium Tel: + 32(0)16 321 391 Email: mah-mausp@kuleuven.be

© Copyright by K.U.Leuven Without written permission of the promotors and the authors it is forbidden to reproduce or adapt in any form or by any means any part of this publication. Requests for obtaining the right to reproduce or utilize parts of this publication should be addressed to K.U.Leuven, Faculty of Engineering – Kasteelpark Arenberg 1, B-3001 Heverlee (België). Telefoon +32-16-32 13 50 & Fax. +32-16-32 19 88. A written permission of the promotor is also required to use the methods, products, schematics and programs described in this work for industrial or commercial use, and for submitting this publication in scientifi c contests. All images in this booklet are, unless credits are given, made or drawn by the authors (Zambeze Studio, Spring 2018).

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RE-EMBEDDING SETTLEMENT IN A REINFORCED OPEN CANOPY LANDSCAPE

2017-2018 K.U.Leuven, Master of Urbanism and Strategic Planning

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Acknowledgements We would like to express our heartfelt appreciation to the people who help us make the outcome of the thesis.

To Bruno De Meulder, our promoter, for his constructive comments and patient guidance of the thesis. During the meeting with him, he gave us a lot of inspiration and practical method.

To Wim Wambecq, our co-promoter, for his help and guidance during the two-week study trip in Mozambique with his enthusiasm. Also the constructive comments during the studio work.

To everyone in Mozambique, who help us with our field trip. With local people’s help, we got a lot of useful information for our research and thesis.

To everyone in the studio, I learn a lot from each of you and enjoy a lot.

To my family and friends, for their sincere interest and support.

To my parents, for all the unconditional support and help.

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Abstract In rural areas of semi-arid landscape such as Changara, characterized by extensive areas of dry forests and increasing urban pressure in territorial and water resources, erosion process has been highly accelerated during last decades.

This thesis discusses the changes in Changara, therefore causes of land degradation and the relationship between habitation and its environmental setting in the Changara by reading the landscape, especially water and forest. It can be seen that water has been one of the strongest driving influences for structures in both the natural and settlement environments. Water events can effect dramatic changes to such fragile landscapes. With modernization, the morphology is nonetheless influenced by the flow of water. Water reshapes topography through erosion and sedimentation, digs new wadis, allows emerging vegetation, curves trails access to resources, and alters the structure of plains. Facing the critical questions at hand about climate change and other man-made alterations to natural systems, water-related intertwined systems is the key to renew the living framework to allow the communities co-evolve with their fragile environments.

The thesis proposes a water management approach, figuring measures that sustain low tech and cost inputs for greening the drylands, by working with the natural water cycle.

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Content 1, Luenha-Changara

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01, Introduction -Luenha-changara, a city between a forest and a river 02, The structure of Luenha-Changara -Organic networks -Gridian networks 03, Changes under the internal and external forces -The forest Deforestation and reforestation dynamic The driven forces behind living in th forest -The water cycle 2, Case Study

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01, Natural vegetation evolution by water re-distribution 02,Community evolution by a holistic water management 03,Micro-catchment water harvesting systems - integrated with planting strategies 3, Design proposal

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1, LUENHA-CHANGARA

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Changara is located in the southern part of Tete, the case which is the furthest away from the Zambezi River in the study area. On the East, it is bordered by the Luenha river, which is a tributary of the Zambezi which comes from Zimbabwe.

Changara-Luenha, a rural settlement with a population of approximately 18000 inhabitants that survive mainly on subsistence agriculture and rearing livestock (2014 Census), is chosen as a example to present settlement in the semi-arid territory.

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Dorne picture, the view from south to north

Dorne picture, the view from north to south

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01_A settlement between a forest and a river Luenha-Changara The site ranges from the forested mountains, over the plateau where the dispersed settlement is reorganizing itself and the riverscape, 40 meters lower where riparian agriculture is practiced in tune with the seasonal rhythms. The severe climate oscillates between long dry and short wet seasons.

As the population increased, settlement areas grow and the cattle overgrazes, severe signs of environmental degradation can be seen. On the riverside, the landscape is ever-changing: the severe and growing erosion gullies are reclaimed to riverscape since little green cover and changing river course, forcing the population to move back every few years, but never completely abandoning the place due to its proximity to their main source of water. Massive deforestation and enormous erosion Monte Mangomana and changara district on the plateau

harden living conditions and leach the existing Miombo Woodland, an open savannah with native vegetation, with many Baobab, Acacia and Mopane trees. The situation is getting worse and people have to live with the risk and conflict.

Plateau, Cliff, slope and Luenha river

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A thin canopy forest dominates the high lands (mountains), deforestation is endemic but clearly linked to accessibility to settlement.

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02_Structure of Luenha - Changara

Organic networks Organic under the “rule” The relationship or the similarity between the different organic networks is striking. In general, they all show two dominant orientations, northeast-southwest and its perpendicular direction. The erosion gullies and streams are oriented in the same direction, and the erosion gullies growing inside the plateau are overlapped with the streams near the cliff. The trails follow the streams or are perpendicular to them. Often, they share the same way. Those three networks intertwine into an integrated network, dominating the region.

Trails, dry river/streams, erosion gullies, nothing is separated.

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Unpaved roads

The gridian networks The “Fake real” Grid Because of its strategic location, Changara has an infrastructure network including the national road EN103, territory road and high voltage power line. Two national roads onewhich connects the province to the south of the country and another to its neighbouring landlocked countries (Zimbabwe, etc).They mainly serve globally instead of adding value locally. On the contrary, the erosion grows much fastern after the construction of the national roards.

Besides, subgrid related to asphalt road is built to organize original settlement areas and resettlement areas. On the one hand, the grid which supposed to be modern hard paving, is a fata Morgana. It turns out to be nothing else than trails.On the other hand, they are there as an indirect way identified by fenced plots.

The structure of Luenha-Changara which can be considered as its infrastructural system is ever-changing and end up with the co-existing of conflict and adaptation, but the most prominent remain the organic networks used by the local population and water to circulate within the territory.

The authority resettlement plan provided by Changara district Initially, the plan is to replace the whole area with imposed grids, but only a small part is realised. Besides, the further away from the centre of the settlement the grid gets, the less it is felt.

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03_Changes under the internal and external forces - The Forest

In a ever-change landscape - evolution of natural forests, forested mountains, deforestation within the settlement, emerging vegetation in erosion gullies

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Dynamics of deforestation and afforestation As the main resource here, the forest is cut down for timber. People also cut down and burn trees in order to increase space for grazing, agriculture and housing.

With reasonable forest management and rotational system, the forest present a dynamic balance.However, in the last 20 years, the external capital and a large number of immigrants result in massive deforestation.Under the external and internal forces, the “fragile balance” in this harsh environment has been broken.

Sources: Landsat(19870413,19930515,19980412, 20040615,2009429,2018520）

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2500

2000

1500

Number of kilns detected per year in Changara

220000

Population growth in Changara

The driven forces behind

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Deforestation can be attributed to internal and external forces. a) Internal forces The annual population growth rate averaged 2 percent in the Changara district, and this is partially because many people migrate from Zimbabwe, which brings increasing pressure on the harsh ecological environment. Increasing population requires more space by clearing forests and also more forest products for domestic uses.

-Grazing Each person in Luenha-

500

Changara has, on average, one animal. Overgrazing is causing erosion and is jeopardizing natural forests.

40000

-Subsistence agriculture 20000

2007

1997

2017 2008

2014

Population growth and Number of kilns detected per year in Changara Source: República de Moçambique Ministério da Administração Estatal; Sedano, F., et al.,2016

New areas on the way to Zimbabwe are cleared for agriculture since the farmlands along the riverbank is insufficient for the increased population.

-Resettlement program With the expanding erosion, the population is forced to find new places to settle, creating significant deforestations to implement resettlement programmes initiated by the government.

- Charcoal production for urban energy consumption Unsustainable charcoal production used in the primary areas supplying charcoal to Tete City causes continuous loss of forest. The charcoal production is considered as the main driver of forest degradation in the study area in the Changara district( Sedano, F., et al.,2016).

Study square

(Left) Kilns mapped in the very high-resolution satellite images in the production area of the Changara district.

(Right) kilns - charcoal production pattern Source:Sedano, F., Silva, J. A., Machoco, R., Meque, C. H., Sitoe, A., Ribeiro, N., ... & Tucker, C. J. (2016).

The impact of charcoal production on forest degradation: a case study in Tete, Mozambique. Environmental Research Letters, 11(9), 094020.

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timber market. As a major raw material supplier,

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Mozambique, especially in Tete province, allows cleaning of vast tracts of forests for logging to export to global furniture market. Moreover, a lot of

GDP growth rate of Mozambique

b)The external forces mainly come from the global

Timber export from Mozambique(m3)

The driven forces behind

250000

deforestation is considered illegal.

0

50000

1980

1990

2000

2010

GDP growth rate of Mozambique and timber export from Mozambique (m3) Source: Department of Inventory of Natural Resources, DNTF, Mozambique; World bank group

Global chain of wood-based products (2016) 90% of timber from Mozambique exports to China, and it is recorded 50% of timber export is illegal.

Source: http://www.globaltimber.org.uk/ChinaIllegalImpExp.htm

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Living in the forest After endogenous and exogenous process, the environment contains variety of vegetation cover from mountain down to river. And they play important roles for local people. The following analysis show the way of life that is embedded, immerses within this environment.

Farmland on the riverbank, forest on the plateau

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Vegetation in settlement

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11 9 8 6 7 3 4 5 2

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Vegeta�on in the riverscape which including riverbank and erosion gullies

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Vegeta�on in the se�lement areas on the plateau

Vegeta�on in the dry forest and mountain areas.

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People can go the other side of river by bridge. And the surface becomes rocky.

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Visualize the change of vegetation The vegeta�on coverage and types change from mountains to the plateau to riverscape.

There are several access to the river and this is one access made by excavators[5]. There are dense vegeta�on[4] on the slope between the plateau and the river. The farmlands are along the riverbank.[3]There are wetlands and wild animals on the islands in the river.[1,2]

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There are severe and expanding erosion gullies near the cliff, and there is o�en dense vegeta�on in the erosion gullies[11].The dry river expanded by eroding provide access to the river with diverse vegeta�on and therefore offer shade[9].Eucalyptus trees are introduced for protectng the soil from eroding[8].

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Overgrazing lead to degrada�on[14,15] near the cliff but natural vegeta�on grow fast in the erosion gullies[12].

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The only na�ve forest[24-26] in the se�lement area is the cemetery which next to the aerodrome[23].Next to the cemetery, there is the rese�lement area with grid plots[27,28].

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The people once lived near the cliff, and they are relocated because of the erosion[22]. S�ll, some people choose to live here[20,21]. Erosion here[17,18] grow much faster than normal level, and the pipelines supposed to be in the groud are exposed[19]. To control erosion, local people put the stones to cover erosion gullies which does not 22 work well[16].

In the se�lement areas, there are some shaded trees and diverse cul�vated vegeta�on including trees inside the plots and so� fences made by live trees[29-31].On the edge between the se�lement area and forest, the se�lements became embedded in the 32 environment[32].

Vegeta�on in the forest is diverse, ranging from From the majes�c, dispersedly present baobab tree[33-37] to middle-high trees to other lower shrubs and low grasses. The forested mountain has rela�vely denser middle-high trees[42,43].

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Living in the forest Sustainable villages maintain this productive forest landscapes on the slopes and mountain areas, complemented with the riverscapes where agricultural production is more evident.

The motion between the valleys and the slopes represents the range of economies from agriculture to silviculture. The forest provides a large range of ecosystem services and social and cultural uses: medicine, wild fruit, bark of the tree as material, charcoal, erosion prevention, protection from drought, livestock grazing, symbolic place for religion, gathering place shadow. The forest therefore brings together a range of people.

Around the baobab for a moment of prayer with the community, under the tree for family dinner, in the field for moment of shadow between the workers, under the cajoeira (cashew nut tree) while waiting for the bus, or selling your products, etc.

Sources: Atlas para Preparação e Resposta contra desastres na Bacia do Zambeze, field trip interview

The local people treat trees the same as buildings.

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Living in the forest The term “house” means not only open and built-covered spaces, that the family nucleus uses on a daily basis to satisfy the domestic needs of its members, but also the open space inside the homestead with multiple uses, the semi-protected space of the canopy, the shade of the veranda or the shade of a tree and vegetation fences.

Usually, all the activities, such as preparation of meals, the personal hygiene, the strong and protection of food, the accommodations, have specific and isolated spaces. The free space of the courtyard with the shaded tree is the binding element of the built space, and it is the centre around which family daily life revolves. The

Legend

following analysis shows the relationship between built-covered space, trees-related

Baobab tree

free space and road systems.

Other trees

The following 5 samples are chosen to show the relationship between the trees

Building

distribution and settlement fabrics. They can divided into two types.

Eroding edges

- In traditional settlement areas - embedded compound

Streams/dry rivers

- In resettlement areas and hybrid areas - built Agro-forest

Trails

The vegetation maps show the space covered by trees and the opposite space which

Asphalt road

means roads, buildings and open space. The analysis maps only pick the trees in the settlement areas.

The legend of following analytical maps

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1KM

1KM

Embedded compound A The area is located on the other side of the river, as a typical example of the traditional settlement pattern. As the structure/an enclosure of compounds, the diverse native big trees, are arranged in a ring form with a cluster of buildings inside. Trails are links through big shade trees leading to compounds, river and forest. Baobab trees are “landmarks”, at the intersection of the trails, with open space around without occupation. It can be seen the density of trees are higher than the density of buildings.

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1KM

1KM

Embedded compound B The expand settlement area located in a deforestation area close to the foothill present an organic pattern shaped by native trees and trails. The areas with shade trees are first occupied, leaving other space for future needs. The smaller-size trees with multiple uses, such as Acacia, Ndodo and Quinina, are introduced into the plots. Trees and buildings have a similar density.

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1KM

1KM

Built Agro-forest The hybrid areas are characterized by a mixture of traditional settlements and standard plots. These two type of settlement patterns are adapted to each other and end with coexistence.

The distribution of the native shade trees, which have a bigger size, and trails are oriented in the same direction. And building, as well as introduced plants, are densified inside the compounds of both patterns. The density of housing is higher than the density of trees.

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1KM

1KM

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1KM

1KM

Built Agro-forest In resettlement area , the remaining trees with the organic trail-like pattern and organic trails still can be seen on the top of imposed grids. However, the modern living concept with fenced plots and wide roads in between is introduced by government. Therefore, the standard housing plots(30m *40m) structured by the grids, affect compound layout. The buildings and introduced plants are arranged inside the orthogonal grid but still based on old logics.

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Living in the forest Although the settlement areas are built after deforestation, diverse native shaded

The interaction between trees and housing changes From compounds embedded

trees are kept inside the plots. Besides, new productive trees are introduced into

into shade trees to introducing productive trees into compounds, from keeping

the living environment. No matter in the traditional settlement areas, the hybrid

big native trees to plant productive trees, from much higher tree density to higher

settlement areas or resettlement areas, it shows certain relations between tree

building density. In any case, trees are most important infrastructure to build living

distribution and settlement fabric. Trails are links through big shade trees leading

environment.;

to compounds, river and forest.

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03_Changes under the internal and external forces - Water cycle The scarcity of water in Changara is a big issue. There is a formal water supply

Rainwater accumulated from the large area with the rocky surface in the south of

system only benefits a few people who live in the resettlement area on the south

Mountain Mangomana, flows through the mountain. The vegetation absorbs and

of the cemetery and public buildings along the asphalt road. There is no hand

slows down the water, and a small part of rainwater percolate deep into the rocky

pump on the plateau since the low groundwater level. Most people have to walk

soil. The rainfall becomes surface run-off gush down to the dry river at the foothill.

down 40 meters from the plateau to the riverbank to find the only one hand pump

More water infiltrates into the ground around the dry river. The soil of the gentle

in the area or directly to the river. Lack of formal and informal infrastructure of

slope area at the foothill is sandy soil which allows water to infiltrate quickly. In

water management, the water cycle in Luenha-Changara is mainly affected by the

addition, the massive deforestation in these area reduces the ability of the soil to

geographical condition, namely topography and subsoil. Moreover, the asphalt road

retain moisture, forming the underground runoff and recharging the underground

construction and deforestation change the water cycle in a more unsustainable way.

water. Going down the slope areas, the soil changes to clay which have extremely low

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infiltration rates and high runoff. The vegetation in the forest absorb lots of water,

eventually evaporates by harsh sunshine in between short rains. And there is

while the runoff increased in the settlement area with bare clay soil. The asphalt

litttle machambas that captures water to stay wet longer when they extract the soil

roads interrupt the natural water flow and accumulate runoff on its both sides. In

to make bricks.

the end, the heavy runoff flows into streams/dry rivers to erosion gullies along the cliff, to the riverbank and finally enters Luenha river together with underground

Besides, the establishment of several dams upstream change the water cycle

runoff.

on a larger scale, which means the seasonal dynamic becomes more and more uncertain and extreme. The rainfall will become more short and sharp, and then

The surface runoff significantly increased in recent years due to the reduction of

the surface runoff will further increase which further accelerates the process

vegetation cover, leading to a series of problems. What’s more, the short, sharp and

of erosion while more water will evaporate, making it more difficult for getting

abundant rains during the rainy season is hardly utilized on the site, and most of it

through the long dry season.

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trees inside the plots to make micro-environment to improve the living environment.

With the development of the city, the environment capacity becomes not enough for meeting the need Mountain

Plateau

of increasing demand for resources including grass,

Riverscape

wood products, etc. from the inside(the growing Organic networks

population) and outside(regional and international

reclaimed by riverscape

actors). The current development based on road

Erosion gullies

Forest

Trails Deforestation, leaving big shaded trees

Trees

construction

River

Dry rivers/Streams

Buildings

Introduced plants

Asphalt roads Gridiron networks Increased population Timber harvesting Overgrazing

Forest

Erosion gullies Dry rivers/Streams Trails Trees Rectangle grid

River

Structure of compounds

Buildings Introduced plants

Asphalt roads

Native forest deforestation

The diagram to show the living framework in Changara and the relationships among different elements.

grassland

The water and forests are fundamental to the Luenha-

integrated links between compounds and big shade

networks Changara. Firstly, they are two mainOrganic resources that

trees. There are often big dense trees near the streams

provide diverse economic systems forErosion local gullies people.

where the soil is more humid. Water is the meeting

Secondly, the hierarchical andrivers/Streams vegetation Forest water Dry

point to integrate different elements.

River

organic networks between the main river and the Trees

Structure of compounds

densest vegetation show the interaction between

embedded in the landscape, and people manage the

landscape and built environment. The erosion gullies

natural resources in a sustainable way. The indigenous

grow along streams and are also caused by streams.

strategies to survive in this harsh semi-arid landscape

In some cases, the stream network which represents

can be found in locals. People cut and manipulate

flows of water and the trails which indicate flows of

trees in a sustainable way by following the seasonal

people share the same way. Therefore, on the basis of

rhythm and respecting the natural forest dynamic.

streams networks which are water flows, trails also

They build housing under the trees or plants the

system provide the structure for occupation.

Trails The

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partial

implementations

of

centralized water pipeline and resettlement program

Structure of compounds

Rectangle grid

and

Under this structure, the settlements were once

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2, CASE STUDY Literature in natural vegetation evolution, agro-forestry, agro-ecology and on other vernacular rainwater harvesting techniques were studied in detail to identify best practices and understand plant-water relationships that enhance resilience to response to climate change and human activities. By doing this, a modernised model that combined water harvesting and planting, permanent green and temporary engineering can be developed.

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01_ Natural vegetation evolution by water re-distribution

- Self-organized vegetation patterning as an adaptation to climate and human impact on semi-arid ecosystems Patched vegetation, with striped, spotted or arc-shaped patterns of different plant life-forms (grass, shrub and tree), has been described in dry zones of

Africa,

Australia, etc, on soils ranging from sandy and silty to clayey (Tongway et al., 2001).

Patched distribution is the result of a long-term adaptation of vegetation in waterlimited environments, and its succession process can be used as an indicator and adaptation of changes of ecosystem response to climate change and human activities.

-The ecological hydrological process of patched vegetation The key for the formation and stabilisation of patched vegetation in the semiarid environment is the water redistribution of runoff from the patches without vegetation to patches with vegetation in different spatial scales. Bare land is the source area, while patched vegetation is a highly efficient water harvesting system, being the sink area in the whole ecosystem and playing an important role in controlling erosion(Du, Yan & Dong., 2012).

Regular maze patterns of shrubs and trees in West Siberia(Source:Photo by W. Bleuten and M. Wassen, 2004 The University of Chicago)

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On the slope scale, there is often an asymmetric

-The interaction between vegetation and hydrologic

distribution from the uphill to the downhill. The

processes is particularly tight in water-limited

uphill slope is mainly composed of seedlings and

environments. Redistributing water in the single

some water-consuming plants, and the middle

patch and multiple patches scales are crucial and

is composed of flourish woody plants, while the

fundamental for restoring the vegetation in the

downhill direction is mainly settled by some poorly

semi-arid area. Water redistribution can be achieved

growing vegetation (Leprun,1999).

by simulating the ecological water harvesting mechanism, using or reconstructing topography, and

-The interaction between vegetation and hydrologic processes

In addition, the patched distribution pattern is also

therefore changing the hydrological process of the

affected by the amount of rainfall and soil types.

ecosystem.

From the regional scale, with the increase of rainfall, There is always some micro-topography in the

the width ratio of bare soil to vegetation patches

- The density of patterns is determined by the

patched vegetation distribution areas. Therefore,

in the same soil texture shows a decreasing trend.

resource capacity in terms of rainfall and soil

surface runoff is redistributed at a single pattern

When the rainfall is similar, the order of the ratio

conditions, and patches with and without vegetation

unit scale and slope scale, which leads to spatial

of bare lands to vegetation patches width is sand >

are equally important. The drought tolerance

variability of soil moisture in different areas and

loam > clay, which is consistent with the change of

characteristics of the species need to be combined

indirectly affects vegetation distribution.

the soil infiltration rate. The lower the infiltration

with the regional (micro)topography.

rate is, the easier the runoff occurs, the smaller The soil moisture content increases in the areas

patches of bare land are needed to produce enough

where runoff flows and these areas are generally

runoff to maintain the growth of vegetation patches.

located in the depression, which are conducive to the emergence of seedlings and suitable for the settlement and expansion of vegetation patches.

Self-organized plant patterns are particularly known from woody stripes that grow parallel to dry slopes. This image from 2017 shows Acacia trees that catch water along a mountain slope in arid Australia(Source:https://www.namibia-eco-tours. com/).

-Enlightenment on Vegetation Restoration in Semi-arid Areas

Aerial view of a tiger bush. Tiger bush is a naturally occurring variation of vegetative strips that harvest water.Average distance between vegetated strips 50m, shaped like w, Niger (Source: N.Barbier).

Banded vegetation patterns on gentle slopes in Niger(Source: N.Barbier).

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02_ Community evolution by a holistic water management

- Community and agricultural development in Zvishavane, Zimbabwe “Water is like blood-it is always attracted to the wound. Gullies are wounds. Blood goes to the wound to coagulate and heal it. It does this with gabions and swales where the gully is filled with fertile soil.”

– Zephania Phiri Maseko

Since the late 1960s, Zephaniah Phiri Maseko, a farmer in Zvishavane, Zimbabwe, has pioneered a innovative vision for community and agricultural development through a water harvesting system which has been widely adopted to increase agricultural productivity and resilience in this semi-arid region.

The Soil in Zvishavane is various from the bare rock outcrop at the top of the hill, to the to the thin, grey soil(are predominantly sand) in the homesteads immediately below the hill, further down to the deeper, darker and less stony with increasing clay content in the cropping area in front of the road. The average annual rainfall in Zvishavane is 450 mm, but can be as little as 250mm during droughts. The amount of water, which comes from periodical heavy rains, erodes the soil, causes flood damage and quickly evaporates in the hot sunny days that follow, is transformed and available to crops by following strategies(Oakland Institute & AFSA).

Map of the Phiri family farm (Source: www.HarvestingRainwater.com)

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Water Harvesting Slow down water movement—thereby maximizing erosion control and infiltration to ensure that every drop of rainfall is fully utilized -construct dozens of stone walls, earth bunds, sand traps, run-off dams along the boundary of the bare granite, ditches around homesteads, and pits above the contour ridge and down the fields, to enable the more gentle down-slope flow of water into the field region below to avoid erosion.

-build deep pond by walls with function like dams in wetlands and using the excavated clay and termite mounds to make a sealed dam wall, keeping the water in the field

Agro-ecology -practices a wide diversity of crop rotations tailored to meet the different soil-water conditions and to help manage weeds, pests and diseases.

-emphasis on perennials with various benefits: they have deep and extensive roots, which can access water and nutrients at a deeper level, slow down water runoff, also have a stabilizing effect by tying up the soil and preventing surface erosion by wind and water.

-integrate livestock into agriculture ecosystem:field crop residues and hand cut grassed that sustain the contours and drainage lines can be provided to livestock. In turn, livestock manure sustains the fields’ fertility, and animals provide the extensive draught inputs(Oakland Institute & AFSA).

(Top) Water management innovations on the Zvishavane farm (Middle) Direction of water flows in the fields (Bottle) Diversity of crops cultivated on Mr. Phiri’s land (Source:Oakland Institute & Alliance for Food Sovereignty in Africa AFSA)

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Large scale of fish-scale pits on the hill-gully Loess Plateau in a semi-arid area (Source: Du zi)

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03_Micro-catchment water harvesting systems - integrated with planting strategies The (re)establishment of a close relation between water management and

confined surface where plants are grown. The runoff is guided and infiltrates into

planting techniques (perpetuated in vernacular irrigation techniques) is required.

an application area where is shaped like holes, pits, bunds and basins to be used to

Indigenous water harvesting techniques can be quintessential references.

grow plants. The size of the catchment can easily be controlled by the farmer, which makes the system easy to adapt and replicate. The MWH system consists of small

Micro-catchment water harvesting (MWH) systems are widely distributed in the

systems replicated many times with identical designs.

semi-arid areas to be used in the productive rehabilitation process, and are suitable to high rainfall variability, reducing erosion and flooding. Unlike macrocatchment approaches, in micro-catchment systems, catchment and application areas are alternating within the same field, thus rainwater is concentrated on a

Negarim (Source: https://www.doc-developpement-durable.org)

Half-moon ditches or demi-lunes (Source: Harouna Sana)

Fanya juu terraces in a semi-arid area which have developed over time into benches. Note the well established grass strips along the bunds(Source: Hanspeter Liniger, WOCAT)

Planting pits( tassa) before planting (Source:FAO)

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Legend

MWH Typology

Water flow Slope Contour line Sedimenta�on Fill

A)Mini-basin

1m Slope

0.5m

Slope

Plan�ng pits (zai pits in Burkina Faso,tassa in Niger,chololo pits in Tanzania)

Negarim

- are small diamond-shaped runoff basins, surrounded by low earth bunds. Runoff infiltrates at the lowest apex, where the trees are planted. They are applied on the sloping land(1-20%), however are commonly found on slopes of 1 - 5% in the areas with an annual rainfall of 150-500mm/y. The reported sizes range from 100 to 400. They are used for fruit trees, but also for the establishment of fodder bushes and indigenous trees.

Slope

Plan�ng pits are mini-basins planted with a few seeds of annual or perennial crops. They are dug by hand. The excavated earth is places downslope of the pit and some�mes formed into a small ridge to best capture rainfall and runoff. They are applied on flat to gently slopeing land(0-5%) that receives rainfall of 350-600 mm/y.

Slope

Slope

2-3m

0.5-1m

0.5-1m

7m

5-

Semi-circular bunds/demi-lunes

-are usually made of earth or stone and have commonly a diameter of 2 - 12m. The bund(height 30-50cm) trips are set on the contour line, facing upslope. They are applied on slopes up to 15%, receiving more than 300mm/y of rainfall. Larger and more widely spaced bunds are called demi-lunes are mainly used for grazing while smaller ones are employed to grow trees for agroforestry systems.

Triangular/V-shaped bunds

-very similar to negarim, these rarthen bunds of about 0.5 m in height enclose a pit in the apex, where the water is stored un�l it infiltrates into the soil. Generally they are applied on slopes up to 20% in areas with more than 300mm annual rainfall.

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2-3m

Fish-scale pits

It is an erosion control measure combined with engineering and vegeta�on, which is suitable for steep slope and broken hilly lands. The scales can be adapt to the slope gradient, which means large pits can be used for medium slope with thick soil while small pits for slopes with thin soil and steep gradient.

B)Micro-basin Check dam

Check dam construc�on is o�en associated with plant cul�va�on, aquaculture and other measures to make comprehensive use of sediment reten�on and water storage. The materials are range from earth, stone to biological.

Meskat

-is rectangular shaped runoff basin. They are suitable on slopes of 2-15% in the areas with an annual rainfall of 150-500mm/y.It consist of a catchment area called meskat and a cropping area called mankaa. They en�re system is surrounded by an approximately 20cm high bund and provided with spillways to allow runoff to flow into the mankaa.

L = H/(I - IC) H I for original gully gradient IC for gradient between the two check dams

C)Cross-slope barriers(vegeta�ve, earthen o�en combined with vegeta�ve)

Permanent vegeta�ve barriers and strips

-are made of grasses, shrubs or trees(o�en combined) to reduce soil loss and increase infiltra�on. It is a technology without structural measures that can be applied on gentle slopes as well as on steep slopes. Since strips are usually laid along the contours, the distance between them is dictated by the slope of the land.

Contour earth bunds - down -slope (fanya chini: “throw it downwards”in kiswahili)

Construc�on of earthen bunds is along the contour by excava�ng a channel anf crea�ng a small ridge down slope.They are used in areas of 300-60mm annual rainfall on slopes of 1-25%.

Contour earth bunds - up -slope(fanya juu:”throw it upwards”

A varia�on of contour bench terraces and are typically constructed on slopes 5-20%.They are constructed by digging a trench and throwing soil up-slope to form a bund. Over �me forward sloping fanya juu terraces can develop into level contour bench terraces due to soil erosion process.

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Upscaling - The various types above are often characterized as simple, small-scale and without need for mechanic operation. However, they are easily destroyed by extreme weather events happening frequently in the wet season and thus require high labour input. In recent years, some of them have been scaling up and modernized in practice.

Vallerani-type basins (mechanised demi-lunes)-mechanization of a traditional water harvesting technology. Use of special ploughs combined with the application of good culture practices and knowledge adapted to local reality.

Mechanised demi-lunes can be constructed by two types of modified tractor ploughs: the “train” and the “dolphin”.The plough has been used for afforestation and pasture. The system can be applied n the slopes of 2-10% gradient in areas of 100-600mm annual rainfall.

Technical drawing (Source: Deserto Verde)

Fast intervention with Delfino plough. (Source: https://www.feedingknowledge. net/home/-/bsdp/5815/en_GB)

Basins waiting for seeds and rain (Source: https://www.feedingknowledge.net/ home/-/bsdp/5815/en_GB)

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3, DESIGN PROPOSAL

55

D

C

B

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A

Re-embedding settlement in a reinforced landscape

The design addresses water and erosion issues and aims to renew a structural frame for living through planting and water strategies that are tailored to the environmental conditions. Human occupation can be embedded and integrated within a resourceful and self-renewing landscape that can bridge and mediate the extreme realities of the dry and wet season, and more importantly, be prepared for future development.

The project for Luenha links and crosses its different elements (mountain, plateau, cliff, riverscape).

Water harvesting From the mountains, rainwater harvesting strategies are explored. Infiltration systems that slow down the water and green the slopes are introduced to allow cultivation. A process of reconfiguration of the settlement on the plateau is induced by systems of water harvesting and optimization of water use. The resulting vegetation and landscape thereafter, gives direction to the redefinition of inhabitation in the harsh semi-arid environment. Erosion gullies are remediated and reconfigured as new productive patchworks, stitched with tree plantation schemes. As such, rich passages between the riverscape and the plateau are organized.

0.5KM

1.5KM

(Plan view) Luenha - Human occupation is integrated within a self-renewing landscape, through planting and water strategies that are tailored to the environmental conditions. It shows a scenerio for reactivated plateau landscape with water harvesting project on the foothills of Monngomane mountains, mixed farming in the settlements and intensive cultivaation in the reclaimed erosion gullies（Sourse:E.Mavie, D.Muiruri, X.Xiao, X.Ordoñez Carpio).

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Colophorspermum mopane (Kirk ex Benth.)

J. Léonard 12m Agroforestry Uses: stabilizing soils; the ash is a useful fer�lizer.

Albizia harveyi Fourn 12 m Intercropping

Berchemia discolor (Klotzch) Hemsl.

12m Agroforestry Uses: windbreak.

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Combretum imberbe Wawra 10m

Afzelia quanzensis Welw (Chanfuta) 15 m Agroforestry Uses: shade tree ; a taprooted plant; poten�al for agroforestry in Miombo woodlands

Albizia anthelmin�ca (A. Rich.)Brongn.

8m Agroforestry Uses: soil protec�on;intercropping

Commiphora mollis (Oliv.) Engl.

8m

Adansonia digitata L (baobab) 20m Agroforestry Uses: Ashes from the shell, bark and seed are rich in potash and are useful as a fer�lizer.

Acacia nilo�ca (L.) Wild. Ex Delile 10m Agroforestry Uses: pioneer species used in reforesta�on projects;against grazing animals; fire-breaks

Cordyla africana Lour 18m Agroforest Uses Shade

Dalbergia melanoxylon Guill.& Perr.

(Africa black wood) 7m Agroforestry Uses: provides good mulch and improve the soil; soil erosion control;windbreaks and live fences

Acacia nilo�ca (L.) Wild. Ex Delile 10 m high, Agroforestry Uses: a pioneer species in reforesta�on projects; tolerate pruning;protect planta�ons against grazing animals;fire-breaks

Colophorspermum mopane (Kirk ex Benth.) J. Léonard Mopane 10 m.

Agroforestry Uses: stabilizing dry;alkaline soils The ash is a useful fer�lizer

Acacia nigrescens Oliv 15m Agroforestry Uses: produce a good quality honey from it.

Dichrostachys cinerea (L.)Wight & Arn 6m Agroforestry Uses: stabiliza�on and soil conserva�on; the leaves are frequently used as a green manure; prevent livestock and other animals

Dichrostachys cinerea (L.)Wight & Arn 8m Agroforestry Uses: stabiliza�on and soil conserva�on; the leaves as a green manure; prevent livestock

Ziziphus mauri�ana 10 m high Agroforestry Uses: fixa�on;s a living fence against livestock

Ficus sycomorus L. 20 m Agroforestry Uses: a shade tree; fixa�on and stabiliza�on; Shed leaves improving the nutrient status, infiltra�on rate and water-holding capacity of the soil;

Ficus sycomorus L. 20m Agroforestry Uses: a shade tree; riverbank stabiliza�on; intercropping

Kigelia africana (Lam.) Benth 20m Agroforestry Uses: erosion control and riverbank stabiliza�on

Terminalia sericea Burch. ex DC. 7.5 m Agroforestry Uses: The species is aggressive and is usually easily established;crea�ng good condi�ons for slower-growing but longer-lived trees of the mature forest. ;a very good pioneer species for use when restoring na�ve woodland ;improves sites by draining waterlogged soils, shading out weeds, and enriching impoverished soils

Tamarindus indica L. 20m Agroforestry Uses: dense shade; firebreaks

Ziziphus mauri�ana Willd, 10 m Agroforestry Uses: fixa�on of coastal dune sand;as a living fence; its spiny stems and branches deter livestock

Senna petersiana (Bolle) LockTronco 8m

Xeroderris stuhlmannii 12m Agroforestry Uses: wind breaks

Senna abreviata Oliv.

3m

Sterculia quiqueloba (Garcke)K. Schum.

20m Trees respond well to coppicing

Pterocarpus rotundifolius(Sond.) Druce 12m Agroforestry Uses: erosion control

Markhamia zanzibarica(Bojer ex DC.) K. Schum. Philenoptera violacea (Klotze) Schrire 8m 10m growing among rocks on dry slopes

Agro-forest

A plant list specific to the Tete-Mozambique region was drawn up with structural diversity and culturalFlacour�a indica (Burm.f.) Merr.

3- 5 m Agroforestry Uses: a close impenetrable barrier that serves as a tall hedge; windbreak or boundary screen

Kirkia acuminata Oliv 13m Agroforestry Uses: water storage that local popula�ons; as a live fence

Pterocarpus rotundifolius(Sond.) Druce 12m Agroforestry Uses: erosion control

Sclerocarya birrea (A. Rich.) Hochst.

17 m

social-environmental benefits in mind.

Legend Edibility Ra�ng Medicinal Ra�ng Other Uses Ra�ng Growth Ra�ng

The plant panel（Sourse:AA Sitoe., & MP Falcão, 2012; http://tropical.theferns. info/)

59

Cut and fill

D Sediment accumulation with water flow Humid subsoil A

B

C

Diagram of single infiltration system unit including 4 elements: A,canopy and grazing land;B,vegetation mound;C,farming land;D,tree strip;

Building infiltration The top view of the model shows series of infiltration systems slow down, guide, spread and thereafter use water.

This allows for a new natural environment to emerge and allows human occupation within it.

Project A , 750x150m, 1/500 (150x30cm)

A

A

High Land Sedimentation capture through water flows from the mountain

Dispersed water flows and consecutive sedimentation make soils fertile and humid. Afforestation is anchored on this spatial device.

The infiltration system builds a micro-environment, including: -vegetation mound which guides the water -farming land before the mound where the soil will be more humid -canopy and grazing land on more dry soils -tree strip on the edge, orientated to wind direction

The infiltration system adapts to different uses and scale

Merging into existing vegetation

Low Land

Model Legend Exsiting forest

Soil Sediments

Proposal Agro-forest

The vegetation mound

Proposal farming land

Proposal grazing land

60

Flooding land

50m

150m

Building infiltration The project is located at the Foothill in the mountain

It is a combination of temporary engineering and

humid

and slope areas, where the natural water flow goes

permanent green. The temporary engineering, stone

-Canopy and grazing land on a relatively drier land

and suffers from the massive deforestation in the

check dam with soil cover, can against event weather

after the mound. A continuous grazing landscape

last 30 years. Therefore, the area has increased water

in the short time. And the permanent green that

is created with shade, therefore, the grass can grow

runoff, resulting in gigantic erosion from settlement

grow on the mounds over time can be resilient to

back faster.

areas to the cliff.

the future uncertain environment in the long term.

-Tree strip on edge oriented to wind direction

The system can be applied either by manual work or

The soil condition of the area is sandy soil with a

machines.

The system with triangle shape is flexible and can be adapted to different scales for different productive

thin clay surface. So it has the potential for reducing runoff and recharging the groundwater. The project

The infiltration system builds a micro-environment

uses: agro-forest, intercropping farming, grazing

is building infiltration to slow down, guide, spread

with an interaction between water re-distribution

or combination of them. In this case, there is a

and thereafter make use of water. Besides, the

and planting pattern, including four elements.

transition from the more water consuming activities

system also captures the sediments through water

-Vegetation mound which slows down and guides

on higher areas, to dry-farming or grazing in the

flows from the mountains. Dispersed water and

water, on it and planted species that can stabilize it

lower areas.

consecutive sedimentation make soils fertile and

with multiple uses for animals and communities.

By doing so, it will create conditions to prolong the

more humid. Afforestation and reforestation are

-Farming land with an intercropping and rotational

water life and allows for a new natural environment

anchored on this spatial device.

system before the mound where the soil will be more

to emerge.

Infiltration system - canopy and grazing

Infiltration system - vegetation mound and farming

Infiltration system on steep slope - sediment

Infiltration system - wind break strip

Infiltration system merge in existing vegetation

Infiltration system on different scale

A

61

Pterocarpus rotundifolius(Sond.) Druce Trees respond well to coppicing; This species has a symbio�c rela�onship with certain soil bacteria Agroforestry Uses: erosion control;good source of pollen and nectar for honeybees Strategic loca�on with spine plant

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Fodder grass

Kigelia africana (Lam.) Bent Agroforestry Uses: erosion control; soil stabiliza�on; shade;the tree does not compete with nearby crops Strtegic loca�on: below vegeta�on mounds

Ficus sycomorus L. Habitat Prefers a deep, well-drained loam to clay soil rich in nutrients;the best site for trees is next to drainage lines, streams, rivers, springs or dams;lants tolerate lopping.

Agroforestry Uses: as a shade tree ;sand-dune fixa�on and riverbank stabiliza�on;shed leaves form a valuable li�er improving the nutrient status, infiltra�on rate and water-holding capacity of the soil;usually intercropped with bananas

Albizia anthelmin�ca (A. Rich.)Brongn.

Zanga Habitat: Prefers clayey soils but is also known to perform well in deep, loose red sand soils; has a symbio�c rela�onship with certain soil bacteria Agroforestry Uses: soil protec�on; good intercropping poten�al Strategic loca�on: mounds integrated with crops

Berchemia at or near are not agg well to cop Agroforest windbreak

a discolor (Klotzch) Hemsl. watering points, as its roots gressive;the tree responds ppicing and pollarding. try Uses: k

Acacia nilo�ca (L.) Wild. Ex Delile Habitat Succeeds in a range of soils, including heavy clay soils;tolerate drought or flooded condi�ons;has a symbio�c rela�onship with certain soil bacteria; Agroforestry Uses: a pioneer species in reforesta�on projects; tolerate pruning well which makes them useful as hedge plants;protect planta�ons against grazing animals;fire-breaks.

Strategic loca�on: deforesta�on slope and mound

Dalbergia melanoxylon Guill.& Perr.

Africa black wood Habitat o�en found on dry, rocky sites ; succeeds in a variety of soils, from loamy sands to clayey Ver�sols;demands water and light; symbio�c rela�onship with certain soil bacteria; Agroforestry Uses: improve the soil by nitrogen fixa�on; avoid soil erosion; windbreaks and live fences; Strategic loca�on orienta�on Eastsouth

Dichrostachys cinerea (L.)Wight & Arn Habitat: Shallow roots, succeeds in a range of soils from clays, through loams to sandy soils Agroforestry Uses: For fuel wood planta�ons, dune stabiliza�on, ravine reforesta�on, or erosion control, the spacing should be 3 x 5 metres. Dense plan�ngs help stabilize gully plugs and check-dams.

Strategic loca�on; mountain slope first phase

Colophorspermum mopane (Kirk ex Benth.)

J. Léonard (Mopane) Habitat o�en found on alluvial soils, but also tolera�ng alkaline and poorly drained soils. a very shallow roo�ng plant Agroforestry Uses: stabilizing soils;the ash is rich in calcium and potassium and is a useful fer�lizer.

Strategic loca�on Slope rocky land, linkage with agriculture

A-A Section The productive activities are various from high lands to low lands to adapt different soil moisture conditions.

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Further down to the transect area between forest and settlement, the infiltration

Topview of project B(Sourse: E.Mavie).

system continue works in a different way also considering the settlement tissues to intensify housing and existing forest. It takes advantage of the areas under the high voltage power line while coupling with grazing and agriculture.

Reaching the resettlement area, the surface run-off water is caught and

Topview of project C(Sourse: X.Ordoñez Carpio).

distributed along the pedestrian pathways in order to intensify, restructure and redefine inhabitation.

Finally, when the plateau finds the abrupt cliff and the massive erosion areas, the intervention aims to prepare erosion landscapes for future productive purposes.

64

Topview of project D(Sourse: D.Muiruri).

In sum, the landscape will be reinforced and by doing so, creating a new microclimate and prolonging the wet season which allow for agricultural practice and

Changara settlement: A view from the Leuhna riverscape over the plateau （Sourse:E.Mavie, D.Muiruri, X.Xiao, X.Ordoñez Carpio)

controlled grazing, and extend the already existing natural resources both from the mountain and the river. The settlements are re-structured and re-embedded in its environment, making it more resilient to climate change and future development.

65

Dry season mural - existing condition (Sourse:E.Mavie, D.Muiruri, X.Xiao, X.Ordoñez Carpio)

Tree catalogue

66

Wet season - plan(t)ed condition (Sourse:E.Mavie, D.Muiruri, X.Xiao, X.Ordoñez

Carpio)

67

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Websites AA Sitoe., & MP Falcão.(2012)..Miti Árvores do Projecto Carvão Moatize. Retrieved from chrome-extension://ikhdkkncnoglghljlkmcimlnlhkeamad/pdf-viewer/web/ viewer.html?file=http%3A%2F%2Fwww.vale.com%2Fmozambique%2FPT%2Finitiatives%2Ffostering-economy-mozambique%2FDocuments%2FMitti_-_Arvores_ do_Projecto_Carvao_Moatize.pdf DEKKER, S., & VAN DE KOPPEL, J. O. H. A. N. Landschapspatronen door zelforganisatie. Retrieved from chrome-extension://ikhdkkncnoglghljlkmcimlnlhkeamad/pdf-viewer/web/viewer.html?file=http%3A%2F%2Fwww.landschap.nl%2Fwp-content%2Fuploads% 2F2007-3_126-134.pdf Oakland Institute. Agro-ecology and water harvesting in Zimbabwe. Retrieved from chrome-extension://ikhdkkncnoglghljlkmcimlnlhkeamad/pdf-viewer/web/viewer. html?file=https%3A%2F%2Fwww.oaklandinstitute.org%2Fsites%2Foaklandinstitute.org%2Ffiles%2FWater_Harvesting_Zimbabwe.pdf WOCAT.(2014)Water harvesting - Guidelines to good practice. Retrieved from https://issuu.com/wocat/docs/english_low_fullversion_buch_wh Ministério da Administração Estatal. (2014). Perfi l do Distrito de Changara Província de Tete. Tete. República de Mocambique – Ministério da Administração Estatal.

Retrieved from: http://www.maefp.gov.mz/wp-content/uploads/2017/04/Changara.pdf https://www.oaklandinstitute.org/agroecology-and-water-harvesting http://tropical.theferns.info/

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