THE WATER TOWER

FILTER TANKWater moves through layers of sand and rocks and charcoal.

FRESH WATER TANKWater is here being disinfected with chlorine (an element that occurs naturally in salts). Potable water is here ready for use. The tank has a 42 hour storage capacity.

GREY-WATER TANKWater from the surrounding humidity catchers are collected here and stored, ready to be pumped up into the filter-tank.

STORM-WATER TANKStorm-water during rain season is collected here after going through the storm-water pocket. The tank varies in size (depth) depending on the capacity for the surrounding area to collect storm-water.

TOWER STANDARD CONSTRUCTIONAllows for mass-production which makes the tower economically achievable. The construction meeting ground-floor has a slightly different aesthetic than the above, with high ceiling and openness, creating a sense of public space.

OUTER SKINUnique form in each location., giving the tower a local identity. Possibility of using local materials in a new way, encouraging local skills and know-how in favour of imported techniques.Construction is plugged on to the inner loadbearing construction of the tanks.

FRESH WATER OUTLETA space for social gathering.

SPILL-WATER COLLECTORWater moving through porous floor and filter, into grey-water tank underneath.

FOUNDATION STANDARD CONSTRUCTIONFoundation below ground level. The standard construc-tion allows for mass-production and is economically efficient.The structure incapsulates the grey- and storm-water tanks.

THE WATER-POINT PERFORMANCES

The tower is a visual element because of its height and recognizable structure. It’s a natural meeting place and a part of the open, public floor.

The water tower makes a shaded, public space, while p.v. panels on the top provides a lighted place at nighttime.

180 m2 pv solar panels, 150 W/m2/h gives an average of (7 hours a day) 190 000 W each day. Water pump needs 740W/h.

THE WATER POINT A VISUAL ELEMENT MEETING PLACE AND PUBLIC FLOOR GIVING SHADE PV. SOLAR PANELS FOR LIGHT A WINDTOWER AND CONNECTOR

Because of it’s natural elevation, the water tower can be constructed as a wind tower, cooling the space underneath it.

The tower may also connect to different public programs, serving as a stairwell and generator.

The water tower captures gray-water and purifies it into public drinking water.

Each tower can hold 50 000 liters of clean water, and 50 000 liters of grey water.

WATER FILTER STATION

The technical build-up of the tower’s elements.In every water-point the bearing inner construction of the tower is identical and thus recognizable, while the variable outer skin is place-specific and makes out a local reference.

LOCAL IDENTITY & SOCIAL SPACE

The skin incapsulates the geometric tower with a dynamic form. The material and building technique of the skin can be varied at each location, creating a place-specific identity and a point of reference.The outer facade creates an air-shaft for ventilation and cooling, as well as it provides with shade. A temperate, comfortable civic space is formed within the tower.

Filter

Fresh Water Tank

Fresh Water Outlet

Manual PumpHere water is pumped by the person

ReuseWater is pumped back into the storm-water pocket when needed during dry season

Grey-Water Tank

Spill-Watergoing into grey-water tank underneath in order to be reused

Storm-Water Tank

Ground-Water Reserve

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Filter 1Sand filter

Filter 2Large stones filter out larger obstacles.

Luanda

Cabinda

Malanje

HuamboBenguela

ANGOLA CURRENT

ANGOLA DOME

BENGUELA COASTAL CURRENT

ANGOLA BENGUELA FRONT

SOUTH EQUATORIAL COUNTER CURRENT

SOUTH EQUATORIAL CURRENT

EQUATORIAL UNDERCURRENT

Lubango

Liquid

Droplets

Liquid

Gas

Gas

Space for social gathering with dry steps when water is low.

C. Vegetation pond with purifying plants.

Walking steps creating access to the vegetation ponds.

B. Wash basin when low water stand, and buffer when pocket is filled to maximum during storm-rain.

A. Rotation pump allows people to manually refill the wash basins and irrigation fields with water from the storm-water tank when needed.

WATER FLOW DIAGRAM

LUANDACombination of currents wind, typography and an arid cli-mate makes Luanda ideal for humidity harvesting.

Luanda lies on one of the driest parts of Angola. The city is pinned against the coast by a high range of cliffs and moun-tains that separate the interior plateou from the ocean.

EVAPORATIONHeat from the sun warms the surface of the water.Some particles of water change state, from a liquid to a gas, due to energy (or heat) from the sun.These particles, called water vapour, then rise into the air.

CONDENSATIONThe water vapour rises as it is warmer than the surrounding air. Air becomes cooler at high altitudes. This cools the water vapour down which causes it to change state back to a liquid. The water particles be-gin to ‘stick’ to each other, forming clouds of droplets.

HUMIDITY HARVESTINGNets made from nylon mesh oriented towards the direction of the prevailing wind will catch about 50 % of the water par-ticles in the humid air. The nets perform best standing vertical, elevated above the ur-ban dwellings.

ACTIVE DRAINReceives water year round from the hu-midity cathers, and rainwater during wet season.

Water from the drain is channeled towards the water tower for purification.

STORM-WATER POCKETReceives rain-water duiring wet season, and holds capacity for maximum amount of storm-water. The pocket change character in tact with the seasons, and functions as a space for social gathering around the usage of water.

COLLECTIONThe water is collected for public use.

WATER TOWERThe water tower is a filter station for water collected from surrounding nets, the drain nerve and rain.Water is here cleaned to potable water, and the wa-ter-point becomes a space for social gathering.

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“Luanda is by far the largest city in the world in which fog farming is practicable. Though Luanda experiences something of a rainy season between March and April, for most of the year precipitation is nearly absent — averaging 0 millimeters/month from June to August — as the Benguela and Angola currents of the Atlantic Ocean combine to prevent the humid air from condensing into rain. This combination of humidity, aridity, and explosive population growth creates a situation uniquely suited to an experiment in urban fog farming”

www.betamammoth.wordpress.com

Based on the experiences of betamammoth, we aim to integrate this quite amazing technique of water harvesting from air into our urban approach. Relying on these numbers, we see the potential of replacing all water truck driving to the musseques with water harvested on site.

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Luanda, Angola Climate Graph (Altitude: 74m)

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Luanda, Angola Climate Graph (Altitude: 74m)

Fog collection works not by condensation, which is what happens when water vapor hits a cold surface and transforms into a liquid. In fact, the water in fog is already in liquid form—it’s just in very, very small drops. As wind blows the humid air through the harvesting net, tiny droplets stick to the coarse woven mesh, made of a kind of plastic netting that is designed to shade young fruit trees. As more and more tiny droplets stick to the net, they clump together and form drops, and eventually gravity pulls the drops down into a gutter. From there, the water flows through tubes towards where the water is captured.

Luanda

Cabinda

Malanje

HuamboBenguela

ANGOLA CURRENT

ANGOLA DOME

BENGUELA COASTAL CURRENT

ANGOLA BENGUELA FRONT

SOUTH EQUATORIAL COUNTER CURRENT

SOUTH EQUATORIAL CURRENT

EQUATORIAL UNDERCURRENT

Lubango

HARVESTING WATER FROM THE HUMID AIR

The humid air from the Atlantic Ocean pulls into Angola’s shoreline as an almost constant drift from the south-east. As the humid air do not turn into rainfall in the dry season, the relative humidity in the air is especially high. In the dry season, the relative humidity is about 80%.

Humidity harvesting nets is a well known technique, used in small-scale at several different places on earth. In the Sahara desert, people have been using simple textiles to harvest water from the air, while woven plastic nets has been used in several projects lately.

This water harvesting seems to work extremely efficiently in small-scale projects -why not extend it to an urban scale?

13 liters/ m2/ day1m2 =

Two workers in Bellavista, Peru, perched 18 feet (5.5 meters) high to sew nets onto a fog-collecting apparatus in October 2007. Conservationists Kai Tiedemann and Anne Lummerich designed this fog catcher--nicknamed “Eiffel” for its metal frame--to collect up to

660 gallons (2,500 liters) of water a day in the foggy winter months from June to November.

When the fog-water starts flowing, “it’s amazing,” Lummerich said.

“It’s like opening a tap.”Bringing the Natural Water Cycle Back

Suitable plastic mesh could be produced locally on rolls

HOW TO DENSIFY THE INFORMAL AREAS WITHOUT OVERRIDING THE INFORMALITY?

“When you no longer improve your house, you are close to death”

ARAB PROVERB

VIANA IS FULL OF EMPTY OR HALF-BUILT STRUCTURES WAITING FOR THE POSSIBILITY TO GROW...

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The moist catchers need to be elevated over the expected densification hight, in order to catch the air drifting from the Atlantlic sea

The nets will need a massive structure to handle the pressure from the wind.

Each m2 should take the pressure of 50 kg, meaning 5 tons on 100 m2.

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What if the structure in itself could make a base for vertical densification of Viana? The structure would be an integrated part of the urban architecture, providing a grid of vertical plots for people to build in to.

The structure will allow for an informally built structure in a grid system providing vertical lots.

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INTERVENTION

ABOUT BUILDING BY YOURSELF / step-by-step

THE WAY PEOPLE BUILD

Finding a free plot. Clearing it.Trees are highly respected, and usually kept, often as shadow space in the centre of the courtyard.

Build the main house, occupy by marking the edges with fences. Extending, fixing, repairing, improving...

“The principal error of the Government is to not recognize the fact that people can do! You see people are building everywhere, they are capable of building their houses.”

MAURICIO, Architect and Teacher in Architecture, Lusiada University in Luanda (ULA)

“Where dwellers are in control, their homes are better and cheaper than those built through government programs or large corporations”JOHN TURNER Brazillian Architect and Urban Planner

In Viana, most houses are built with a reinforced concrete frame, filled in by adobe bricks. Roofs are usually made with corrigated steel plates. Walking in Viana, empty frames and unfinished structures are as usual as finished ones. It is clear that the state of building is a continous one, where materials are bought when you have a small profit, and that adding on and repairing is a constant process of life.

It is obvious that the materials of the houses are chosen by what’s available and cheap. The heavy construction is good for thermal mass qualities, but the thin steel roofs heat up the small houses.

Fill-in concrete frames is the base of self-building in Viana

POSSIBLE DENSIFICATION IN STEPS PROVIDING PUBLIC SPACE

Existing structure Added structure Connecting to structure/house improvement

Possible densifying Existing structure First build, then move

SHADOW AS QUALITYTHE SOIL FLOORTHE CENTRAL TREEHOUSES FACING THE SHARED COURTYARD

DENSIFICATION GRIDS/ Courtyard Logic

The musseques are characterized by one-storey houses densly built in connection to a variation of courtyards. The creation of the court is decided by the original pattern of trees, on which the houses are built around. The courtyard is the semi-private zone between the houses and the street, often halfly opening towards it.

In our densification strategy we use the clear courtyards as base for vertical densification, letting the grid cores preferaby connect to these, instead of directly towards the street.

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DENSIFICATION GRIDS

STREET

black water treatment

humidity harvesting

sanitation core

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DENSIFICATION GRID10x10mWood (local module production, Viana)Light add-on structure

WATER COREConcrete/ bricks (built on site)Rough structure handelling the flow of people and the treatment of water

WATER CYCLE

MOVEMENT FLOW

FLOW CORE

Another add-on structure/ADDING IN HEIGHT

VERTICAL WATER CORE AS SOCIAL ARENA

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Black water ventilation shaft

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graywater runoff towards street

bigger stones etc in the first meter

black water filtering biotope(banana plant)5

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take out fertilizer

CORE WATER FLOW

The core is a standard heavy concrete construction serving water and sanitation on site for the inhabitants of the grid. It’s concidered a rough zone where daily routines, water handelling, cooking, growing etc can happen within a frame of shared water resource. The core is also the flow area with vertical connection (stairs).

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