Second phase of Water and Sanitation Mapping – Intermediary analysis

The second phase of Water and Sanitation mapping is over and with it the pilot in Mathare, which lasted for 4 months. You can read all about the events and the processes leading up to this point on our previous blog entries. I will call this an intermediary analysis because the work is by no means over, but we’re at a good stopping point to reflect and set the way forward.

Map Mathare - Toilets, Water Points and Open Defecation Areas, April 2011

Here’s the data we collected regarding toilets, water points and open defecation areas, and what it tells us (these numbers reflect the data which we collected during our pilot):


  • We collected 144 points of interest where toilets are located in the whole of Mathare. These points have 373 individual units attached to them. These are mostly publicly accessible points, meaning we only took points which are public and, for example, didn’t walk into people’s homes.
  • Most of these toilets are privately owned, with 50% of the toilets having known ownership. The other 50% are owned by different organizations, government, etc. and are considered public.
  • The majority, 50%, of the toilets with known type are Asian Style, followed by 26% pit latrines, and 11% hanging toilets. The rest are trench and English toilets.
  • Most of the toilets are located in the public within the communities; this is because we collected mostly public toilets in the first place. I’m happy to say that 90% of collected toilets are operational.
  • Most toilets are connected to sewage (60%), and have available piped water (54%), and are usually cleaned, either by the operator (38%) or the caretaker (33%). Many toilets have almost non-existent hand washing accessories (37%) and non-existent towel bins (0,7%).

Couple of visualizations of the upper data displayed on maps:

Distribution of toilets in Mathare and customers
Toilets with sanitary towel bins
Toilet connection

Water points

  • We collected 167 water points.
  • 60% of these water points are privately owned. As with toilets, the rest are owned by different organizations, government etc. and are considered public.
  • Most of these water points are piped or tap water (75%), while others are water tanks.
  • As with toilets, most of the water points are located in the public within the communities.
  • 98% of collected water points are operational and have connection to water pipes.

A visualization of the upper data displayed on a map:

Type of water point

Open defecation areas

Open defecation areas cover 16144 m2 of Mathare (3 km2) and their placements vary throughout the slum.  They are mostly located in the areas where there are majority corrugated iron sheet houses, which usually don’t contain toilets.

Open Defecation Areas
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Why Map Open Drainage? And How?

Open Drainage

I believe that the reasons to map open drainage in the slums are well known and are obvious to most people. Everyone who’s ever been to the slums knows that open drainage presents a huge health hazard to the people living around it. In combination with poor or non-existent water and sanitation systems, open drainage presents a recipe for disaster which is always present and can erupt at any time and wreak havoc amongst the populations. If I quote a few experts on the dangers that open drainage poses:

“Potholes in the streets, pools of stagnant water, and waste gushing from bathrooms and kitchens provide breeding sites for malarial mosquitoes and other spreaders of disease.” (Nwaka, Geoffrey I. “The Urban informal Sector in Nigeria”)

“Most slum households must fetch their water from a standpipe and deposit their waste in open drains. The rate of infection is high; therefore there is constant risk of epidemic.” (Gulis et. Al. “Health status of people of slums in Nairobi, Kenya”)

“In slum areas, a minor flood is not just inconvenient. It is life-threatening. With open drains and overflowing latrines even a small flood means that children have to wade through raw sewage.” (Willem Alexander, HRH, Chair of UNSGAB. “World Water Day Op Ed”)

In an article on the health status of people of slums in Nairobi, Kenya the authors conclude that: “Environmental conditions can have major influences on health status. Therefore, environmental improvements are important in the improvement of health status.” (Gulis et. Al. “Health status of people of slums in Nairobi, Kenya”)

As my friend Simon, a long-time resident of Mathare and our Map Mathare Coordinator, put it on the Mathare Valley blog: “One does not need to be a scientist to know what would happen in case of disease outbreak. The improvement of proper water distribution and repairing the broken water pipes coupled with constructing good drainage system is the key to fighting common illness in the slums.”

What I can add to all of this is that in order to improve or at least start improving living conditions, you need to first know and understand the situation on the ground. By mapping open drainage areas, our mappers are providing the first detailed geographical information about how open drainage is distributed throughout Kibera and Mathare, thus providing necessary information to anyone hoping to solve the problem.

This I believe answers the question of why and brings me to the next question: How?

Obviously open drainage creates “appalling living conditions,” but maybe not so obviously, it creates appalling mapping conditions too! Open drainage winds and curves between houses, often sinks below them, intersects, flows, stands, overflows, merges with the content of broken sewage lines (sewage lines burst and sewage comes above ground, mixing with the content of open drainage), and creates pools of standing water. Open drainage is the main collector of garbage: garbage in open drainage areas often clogs drainage systems, thus creating floods during rains. All of this mesh slowly flows downwards, usually towards rivers that pick it up and carry it further downstream, polluting the environment sometimes hundreds of kilometers away.

In order to understand the scale of the problem in Mathare and Kibera we went on an investigative – or, if I put it in army terms, reconnaissance – mission with our teams to see the problem first hand. Our participants surveyed the problem, and their input helped us to better understand what we’re up against. We walked through the slum evaluating different drainage lines and problems we faced in mapping them, Sebastien (our new volunteer) and I then facilitated the mappers to decide on which points of interest we should collect and in what order.

Investigating the problem

Findings from the field regarding open drainage include:

  • Open drainage has many sources and it forms for many reasons (resulting from topography and from human actions)
  • It comes in many forms regarding the content and structure (garbage, water, sewage, earth trench, concrete trench, etc.)
  • It has main channels with many tributaries

We came to realize that drainage systems in slums (Kibera, Mathare) basically work as micro river systems! This made us understand that it has to have an outlet, and both Kibera and Mathare have outlets in the form of rivers that run through them.

All of this helped us made our action plan:

  • All the drainage flows towards the rivers, so we started collecting data along the rivers.
  • The next step is to collect data for the main channels, which lie along the main paths.
  • After this, we focused on the smaller paths in the slum, collecting points of interest along the way. This includes the start and end points for “following” a drainage line, intersections of different lines, man-holes (along sewage lines), and broken sewage lines. At intersections, we’re collecting the directions of different intersecting lines
  • Throughout this process, the use of building extraction (when possible) helps us sketch the drainage lines

After the extensive data collection we’ll use the satellite imagery and building extraction to help us determine the exact positions of drainage lines.

Mapping Open Drainage

So, what’s next?

Just knowing and understanding the situation will not make it better. This means that our process cannot end with mapping, but will take the map and the information we collect a step further to actually make the information useful and create an impact. The next step is bringing together community members, stakeholders, NGOs, local administration and government representatives and expose the problem with a method I like to call: “A punch in the face” – where we present the problem, with maps and other media, in all its vastness, and hopefully get some heads thinking and acting upon the information which is presented. The map lets stakeholders present problems to responsible actors in a comprehensive and difficult to ignore manner, making the issues more concrete than just words by providing detailed geographical representations of their scope and characteristics.

In order for this last step to be successful, local ownership, insights, and understandings of both the issues at hand and how mapping and presenting information can help bring change, is crucial. Creating this local ownership amongst key stakeholders – namely the local Map Mathare and Map Kibera teams – has to start from the very beginning of the process. We are working hard to create this local ownership from the beginning in Mathare and to bring a greater sense of ownership to the Kibera teams.

Map Kibera and Map Mathare are currently involved in vast mapping operations regarding Water and Sanitation in both Mathare and Kibera, two of the biggest slums in Nairobi. These projects are big as the issues they are trying to address and will present test whether exposing vast quantities of information about a particular issue truly has the ability to influence change. As I often say: Collecting data, as complicated and hard as it may be, is the easiest part here.

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First phase of water and sanitation mapping

Jackson collecting a point in front of a toilet

The first phase of detailed water and sanitation data collection and editing is over. In two weeks our teams collected and edited 262 points including: 89 points with toilets, 108 water points and 65 open defecation areas.

What we learned from the numbers:

  • The smaller number of toilets does not show the real picture as there can be many toilets at one point (we collected the number of units per point, but this is not reflected in the 89 figure).
  • The number of open defecation areas is alarmingly high – there is almost the same number of toilet sites as there are open defecation areas – which clearly points to a lack of toilets.
  • The number of toilets and water points will likely stay low because of the specific structure of Mathare: half of its buildings are high-rise apartment buildings that usually have toilets and water connections on every floor , which brings us to the next point:
  • In order to get the real picture of the water and sanitation in Mathare, we need to figure out how to collect the data from these apartment buildings (it will need to be an inclusive approach, connecting community members, stakeholders, administration, government, etc.)

For the purpose of data editing we used basic mapping features to tag our points as amenities, like toilet and drinking water, and for ODAs we used the tag landuse-landfill. In addition to these basic features we added our own tagging scheme which we created so it coincided with the data collection forms.

There was some confusion here and there because of the massive amount of papers which contained the data of different points (something to think about in the future – how to get rid of the huge stocks of paper), but otherwise the data entry itself went well.

Here’s a detail from OSM showing all three features.

Phase two is already on under way.

Water point
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Building extraction of Mathare No10, Mashimoni, Mabatini and Thayu

Although the Ground Truthing of the shapefile which was sent to us by AAAS was done in three days (read more here and here), fixing the shapefile itself took a bit longer. In the process, we created three shapefiles.

The main shapefile contained the closest resemblance to the situation on the ground. Our teams have checked and corrected on the ground the shapes of most of the buildings, written down the types of the buildings, and classified them. From this exercise, 4 attributes were added:

a) Type means the type of building, which is either Brick, Corrugated Iron Sheet, or Wood Stalls

b) Name is name of the building (if it has a name)

Type of buildings

c) Designated is the designated use of the building, describing what the building is used for. It can be many things, including: school, house, business (like bar, cyber cafe, garage, hardware shop, market place, etc.), church, toilet, etc.

Designated use of the buildings

d) Action is what kind of action was carried out on the shape of the building – there are two options: 1) Added if the building was missing and was added and 2) Modified if the building was either moved, merged, or in any other was modified

Action performed

Many times in the slums you see corrugated iron sheet houses build on top of brick houses. We’ve identified these structures in the second shapefile called Buildings On Top.

Corrugated iron sheet buildings on top of brick buildings

The third shapefile contains deleted shapes (buildings) because they are either not there, are incorrect (there are many shapes representing one building), or don’t represent permanent structures (like temporary tents in the Chief’s camp).

Deleted objects

Our teams have collected around 750 points in the first run of data collection and are now it the second phase of detailed Water and Sanitation data collection. The idea is to eventually attach the points they collect to building extraction for the whole of Mathare.

Attaching points to buildings
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How to map open defecation areas

Our teams have started with comprehensive thematic mapping of Water and Sanitation. Most of the things that we set out to map, such as water points and toilets, were pretty straightforward, but there were also some unknowns – like open defecation areas.

What is an open defecation area (ODA)? This is an area which is used by people to relieve themselves where there aren’t enough toilets for all or where people can’t afford to pay to use the toilet (more about it here). These areas are usually also dumping sites for “flying toilets” and other garbage, but mostly for excrement. People use them either early in the morning or late at night so others can’t see them.

Open defecation area

We didn’t realize that this is such a big problem until we saw it with our own eyes. They are a huge health risk because they are usually situated in the middle of a very populated area and it is not an uncommon sight to see children playing near or even on top of them. They are also an indicator that something is terribly wrong with sanitation (especially toilets) in the slum.

So how do we map these areas? The first idea was to stand in the middle of the area and collect a point. We dismissed the idea as soon as we saw the expanse and the state of these areas. Most of our mappers come in flip flops and aren’t well equipped to walk there. So we decided we’re going to take a point near the ODAs, later search for the point with the help of satellite imagery and digitize the area. This way we’ll learn different techniques in mapping, get the exact area (in square meters) of all of the ODAs and therefore the whole area in Mathare which is covered by them.

Below are two examples:

Mapping open defecation areas
Mapping open defecation areas
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Nightly Built in front of our noses

When talking about cities that ’emerge at night’. Here is an example of the buildings being constructed in front of our noses. It took them less than a week to put up a housing unit (tin shack) which contains 8 rooms and will house – if we downsize the number of people to at least 3 per room – 24 people.

Nightly Build

This is yet another example of why it is necessary to have community members trained in mapping techniques – to keep up with the ever changing slum.

Below is half a year old satellite image which shows the same building but without a structure on top.

6 months old satellite image of the building
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Update on video in Mathare (and Kibera)

This is a fairly short and quick update on video in Mathare and even shorter in Kibera.

One of our ideas at the beginning of the video program in Mathare was that video guys would go on the field with mappers and collect what they are doing. We thought this would be important for several reasons:

  • it would create harmony between different groups (mappers and video)
  • this way we would document every step of the process and thus create awareness of the project which could later be used for attracting funders, etc.
  • with public screenings, we could show the community what we’re up to

We then decided that mappers and video teams together would present too big of a group walking around Mathare and would raise too much attention so we dropped the case. Now that the community is aware of our presence, this is again something we can think about.

From the start we always presented all the programs as one and the same thing – getting the info about Mathare out there, with all means possible. When talking about video and unity, the current situation in Mathare is that we have a group of around 20 video guys, many of them also community bloggers and a part of our mapping program, and who want to be involved with Voice as well, because they see all three programs as one.

How we conduct the trainings in Mathare:

In Mathare we’ve partnered with Nathaniel Canuel who has created a very interesting training program with which he is trying to inspire the group to explore their individual talents. For example, to stir their imagination he created a collage of videos from some of the world’s most famous films (Apocalypse Now, The Godfather, etc) – the theme was, “the marriage of picture and sound.” He also showed them several videos which were made in Kenya and some of his own work. After and during they had discussions about different camera angles, sounds, effects, etc.

My understanding from the meetings and trainings is that the participants in the video program want to explore the potential of video. They want to use it to showcase the stories from Mathare, the stories of their friends, relatives, the way of living, etc., and they want to do it in an interesting way.

The trainings usually go on like this:

  • Nathaniel shocks them with all different artsy stuff
  • They hold discussions about things they’ve just seen
  • They discuss different issues in Mathare and how much work a certain issue would need
  • They pick issues and talk in detail about how they will go about it (Nathaniel is guiding them and asking them a lot of hard questions)
  • They take footage and edit

To stir their imagination and make video interesting to the participants and the people watching it, we decided (together with the participants) to do a game or a competition, where very abstract titles will be chosen and then the group will make videos to go along with those titles (this will be a fun addition to the “serious” work they are doing). The videos will be presented at public screenings where the community will decide the winner. We figured people will want to see these videos, and it’s also a way to have some fun. If I quote Jeff: “People here are tired of all the bad and depressing stories, it’s about time we do something different!”

These are just some of the quick updates on how things are going. You can see the first videos from Mathare here and also Kibera News Network is back on track with new videos here.

Oh… The first story which came out of “let’s have some fun” is: Welcome to a Dog’s World by Joe Gathecha from Kibera News Network.

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7% of Mathare has been ground truthed

We have completed the ground truthing of a test area of Mathare 10, Mashimoni, Mabatini and Thayu. The whole exercise took us two days. It took us one day to prepare – determine how to go about it, go out in the field to see how it works, what needs improving and to create proper forms which make sense. Then we divided the area into 11 smaller areas of focus for which we created detailed forms for data collection. By detailed forms I mean an A4 paper with a picture on top. Remember! It’s the execution that counts, he he…

Test area divided into smaller areas

We held a brief meeting on Wednesday, 16.2.2011, with all the Mathare mappers where we talked about the theories behind satellite imagery, building extraction, the importance of collecting such information and explained how the exercise will run in detail.

It took 5 groups 3 hours on Thursday, 17.2.2011, to check all the buildings in the test area, fix incorrect shapes of buildings, write down the types of buildings, and classify them. In other words, it took them 3 hours to ground truth 0.21 square kilometers which represents 7% of the whole Mathare area.

Some of the Data collected

Through the exercise, we’ve encountered some problems which we need to address to AAAS for further clarification and advice. For example, how do we ground truth a big stone building which has tin houses on top of it? Is it one building or many (picture below in a circle)?

Tin buildings on top of a brick building

The next step is to digitize the data collected, send it back to the AAAS, and then wait.

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Ground Truthing Mathare

The American Association for Advancement of Science (AAAS) donated us a WorldView-2 image (read more) with 6% cloud cover, taken on 30th of June 2010. It covers the areas of Mathare Valley, Korogocho, Kariobangi, Baba Dogo, as well as part of Kasarani, Dandora, and some surrounding areas. Altogether, the imagery is of a broader eastern part of Nairobi, containing the areas with the highest concentration of people in the city.

Satellite image of Mathare

The image is of course useful in numerous ways, but the first thing we want to use the image for is to create a building extract for the whole area of Mathare! The AAAS showed a great interest in helping us with this issue and is indeed helping us now. The deal was that we set out a test region to begin with so one of their analysts could analyze that area. We would then take a look at it and go to the field to ground check their mapping. If that worked out satisfactorily, they would expand the extraction further to do the whole area.

As said, we first set out the test region for them to analyze. Our focus was on Mathare 10, Thayu, Mabatini, and Mashimoni. We picked the area because it is situated very centrally in Mathare, has different variety of buildings (tin and brick) and is also an interest area of our partners, Plan Kenya and CCS. A day after the area was set we got the first results – the first automated building extract of the area.

Building extraction on a test area

A quick look already revealed some of the faultinesses of the automated process like overlaying shapes, crooked shapes of objects, shattered uniform objects and merged diverse objects, digitized/mapped non-existing objects, etc.

Some of the faultinesses of the automated process

Our next “job”, which is currently under way, is ground truth-ing the results. This basically means checking every object in the field and comparing it to the created extracts, than confirming or rejecting certain objects, classifying them, repairing the shape files, digitizing collected (repaired) information and sending it back so they can reset their algorithms.

Ground Truthing

The biggest challenge is how do we do that practically with limited equipment and resources? We knew from the start that we’ll get the best results if the people who come from the area are the ones ground truth-ing their own area. This is also important because this kind of work basically takes you into the compounds and backyards of houses and you obviously don’t want strangers walking on other people’s backyards.

For the purpose of data collection I created forms, printed them out, bought some pencils, sharpeners and erasers and called Francis and Jackson from Mashimoni to take me around their neighborhoods and give me the feedback – they are two of the mappers who will be the ones leading the project on the ground later, which is why their opinion is crucial.

Francis and Jackson in action

During the exercise we focused on specifics like:

  • We numbered each house in the test area, classified them and added different types of buildings (tin, brick, etc.)
  • We repaired shapes of the buildings extracted
  • We deleted redundant shape files
  • We wrote down names of all known landmarks

The guys also gave me feedback regarding the forms:

  • Prepare a bigger map of the whole test area and outline the smaller area on it for better recognition of the area
  • Add names of the roads to the forms for better recognition of the area
  • Make darker outlines of extracted buildings on the forms
  • Add names of landmarks for better recognition of the area

After the ground truth-ing of the area the AAAS will (hopefully) expand the extraction to the whole of Mathare. And then the fun really begins!

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Base map of Mathare is complete!

We’ve completed the base map of Mathare. It took us 17 days during which 15 mappers (on average each day) would map and edit for an average of 5 hours per day. That accumulates up to 1250 man hours. Of course the exact figure of man hours is much lower mainly due to a limited number of computers and equipment which resulted in many of the mappers just strolling along or observing the creation of the map from afar. We have mechanisms prepared for this type of instance, as we want everybody interested to learn and contribute. One of these mechanisms, which we implemented in the last two weeks of mapping, is rotating venues.

If I throw some statistics at you, the base map has – or, if I put it differently, mappers have collected, edited and digitized:

  • 750 points
  • 41.3 km of roads and paths
  • 24 Mathare villages digitized, altogether an area of 3006444 m2 3.0064444 km2
  • 138 buildings digitized, altogether  an area of 58322 m2 or 0.058322 km2
  • Other areas digitized (walled areas, fields, football and recreational pitches, natural areas, etc.)comprise 360602 m2 0.360602018 km2

Below is the base map where the first map (Map 1) presents only the points collected and the second map (Map 2) presents the types of resources collected (represented by points), such as hospitals, toilets, water points, schools, religious institutions, etc.

Map 1
Map 2
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