managing at the same time too much and not enough water in accra, ghana

HafenCity Universität Hamburg

M. Sc. Resource Efficiency in Architecture and Planning (REAP)

Urban Water Cycle

Summer Semester 2015

Final Report

Managing at the same time too much and not enough water in

Accra, Ghana

Submitted to: Professor Dr.-Ing. Wolfgang Dickhaut

On: Wednesday, September 30th

, 2015

Contributing Authors

Asiedu-Danquah, Kwadwo : 6028962

Troutman, Heather : 6028601

Abstract

This paper offers a critical review of the state of water in Accra, Ghana. The paper explores the

climatic, cultural, political and historical situation of Accra offering understanding and explanation

for the current state of practice. The paper discusses the means in which water cycles through Accra

including storm water, flowing water, waste water, and the constant interplay these subdivisions have,

highlighting their interdependencies. Contemporary water projects both large- and small-scale are

detailed and criticized. The paper concludes with a suite of theoretical recommendations for

improved water management in Accra through the implementation of small-scale, low-tech and

decentralized proven water management techniques that the authors prescribe to be suitable for the

climatic, cultural, economic and political context in Accra.

Urban Water Cycle: Accra, Ghana 2

Table of Contents

1.Introduction…….....……………………………………………...………………………………..03

2. Accra, Ghana: an Overview………….…………………………………………………….…….03

2.1.

Climate………………………………………………………………………….……………...……..04

2.2. Demographics………..…………………………………………………..……………………05

2.3. Urbanism……...………..………………………………………………..……………………06

3. Storm Water……………………………………………………………………….………………07

3.1. Precipitation Events………………………..…………………………………………...…….09

3.2. Causes of Floods…………………………….………………...…………………………..….09

3.3. Recent Projects…………………………….…….………………….……………….……….11

4. Flowing Water……...……………………………………………….…………………………….12

4.1. Hydrological Features…………………..…………………………………………...……….12

4.2. Current System.……………………………………………………………...……...………. 13

4.3. Recent Projects.…………………………...……………………………………………..….. 14

5. Waste Water………………………………………………………………………………….……16

5.1. Existing Infrastructure and Trends……………………………………………………..……16

5.2. Recent Projects….…………………………………………………………….…………..….17

5.3. Performance Overview………………………………..…………………..……………...…..19

6. Conclusions and Recommendations..…….………………………………………………….…..19

6.1. Solid Waste…………………………………………..…………………………………...…..20

6.2. Urban Agriculture………………………………………..……………………………….…..20

6.3. Storm and Flowing Waters………………………………………………..…………………21

6.4. Waste Water………………………………………………..…………………………….…..22

Figures, Graphs and Tables

Figure 1: Annual precipitation data for Accra for 6 statistical period …………………………….…04

Table 1: Comparison of extreme rainfall events between Accra and Hamburg………………….…..04

Table 2: Projected annual 1day, 2 – 5 consecutive day’s maximum rainfall for Accra.............……..05

Figure 2: Urban growth of Accra from 1985 – 20002……………………………………………….06

Figure 3: Representing the various basins in Accra………………………………………………….07

Figure 4: Schematic of drainage system in Accra, Ghana……………………………………….…...08

Figure 5: Return periods for precipitation events in Accra, Ghana……………………................…..09

Table 3: Historical rainfall events in Accra……………………………………………………….….10

Figure 6: Waste-clogged drains……………………………………………….……………………...10

Figure 7: Odaw Drainage Improvement Works……………………………………………………...12

Figure 8: a. catchment areas, b. discharge rates, and c. runoff concentrations……...…………….…13

Table 4: Total discharge of basins within the study Area…………………………………………....13

Table 5: Phases of the Korle Lagoon Ecological Restoration Project………………………………..14

Figure 9: Odaw River Dredging as part of the Korle Lagoon Restoration…………………………..15

Figure 10: Systematic diagram of the UASB reactor wastewater treatment plant……….…………..17

Table 6: Characteristics of sewage at different treatment stages……………………...………….…..18

1. Introduction

Water is an important resource that is needed by all living things for survival. Its manifestation on

planet earth and availability to humans as a resource is varied with the great diversity of the natural

world. In the urban environment, rainwater is often a primary source for fresh water, but it can also

accumulate at raid speeds bringing devastation to urban infrastructures and posing threat to human

health and safety. A number of countries have enough water throughout the year but are still faced

with problems related to water. These problems are most prevalent in the developing countries where

water is mismanaged leading to long-term environmental degradation, which results in degraded

quality of life for inhabitants of such urban areas.

Major challenges in these countries include problems related to water supply, wastewater treatment

and periodic flood events. It is however clear that these factors are interdependent and cannot be

easily separated from each other. Accra, which is currently fast growing and having a larger portion

of its population living in informal settlements, cannot be detached from this problem. The city and

the entire water bodies suffer from pollution and contamination normally from industries and these

informal settlements. This is because the city’s drainage system is designed in a way that leads most

of the waste from households and industries directly into the lagoons without any treatment before it

finally empties itself in the ocean.

During flood events, most of these lagoons and drainage systems overflow their banks and affect the

low-income informal settlement dwellers. In addition, insufficient storm water infrastructure coupled

with poor waste management and improper planning are other principal causes for floods in Accra.

What makes the situation worse is the fact that most of the population depends on these water bodies,

which are mostly contaminated, as their primary source of drinking water. It is essential that the city

of Accra take immediate investment into identifying appropriate measures to deal with the seasonal

flood events. To achieve this, the city must consider proper ways of solid waste collection and

treatment to minimize the amount of waste that is directly discharged into the water bodies.

The paper examines the interdependencies that exist between storm water, flowing water and waste

water. It begins with a general overview of the nature of storm water in Accra, its current state and a

current project that has been undertaken to deal with storm water. The subsequent section gives a

description of the current flowing water situation and the final section highlights the nature of

wastewater treatment and some current projects.

2. Accra, Ghana: an Overview

Accra is a city located along the coast of Ghana on longitude 0° 1′W and 0° 15′ E and latitudes 5° 30′

N and 5° 50′ N, respectively. It is situated within the Greater Accra Region that covers a total land

area of approximately 1,261 km2 and serves as the capital city of Ghana and at the same time the

capital of the Region of Greater Accra. It is the smallest of the 10 regions in Ghana.

The city is generally low lying and relatively flat with few hilly areas in some parts of the city. The

groundwater level ranges between approximately 4.80 meters to about 70 meters below sea level

(Nyarko, 2002). The city has 8 drainage basins designed to serve as channels for most storm water.

These basins include Kpeshie, Korle, Densu, Sakumo, Lafa, Osu, Songo Mokwe and Chemu Basins

(Asumadu, 2015).


2.1. Climate

Ghana experiences two main rainy seasons; one major and a minor with the former occurring between

the months of March-July and the latter between September-November. The mean annual rainfall of

Accra is about 800 mm (Amoako & Boamah, 2014). Figure 1 shows the mean precipitation for Accra

recorded over 6 statistical periods with 10-years intervals (from 1962 - 2012). From the data, it is

observed that the city of Accra receives most of its rainfall normally between March and July having

mean precipitation values greater than 150 mm/month. In September and October, precipitation levels

again increase but only slightly with mean precipitation values below 100 mm/month. The general

pattern for the various precipitation events over the various months from 1962 – 2012 seem to be

quite uniform apart from 1962 where the month of June experienced an extreme increase in

precipitation of about 700 mm. The months of January-February, November-December and August

receive the lowest rainfall in Accra with mean levels below 50 mm/month. Even though differences

exist in the various rainfall amounts, precipitation of 200mm/hour is possible during the highest

rainfall seasons (Adank, Darteh, Moriarty, Osei-Tutu, Assan, & Rooijen, 2011). The months before

the rainy season (February and March) is the time the region experiences its hottest temperatures. The

mean temperature around this time is about 27 degrees Celsius while June to August experiences the

coolest (Nyarko, 2000).

Historical overview of rainfall events of Accra gathered by Okyere et.al (2012) from different sources

were compared to that of Hamburg. These rainfall events were daily rainfall precipitations that were

recorded by the Ghana Meteorological Agency and gathered by Dickhaut (2015) for Accra and

Hamburg respectively. The data shows the precipitation events recorded for 20 minutes and on both

annual and daily basis (24 hours).

Table 1: Comparison of extreme rainfall events between Accra and Hamburg

Event Accra Hamburg

Year of most Extreme

Precipitation

4th July,1995 18

th August, 1994

Highest hourly rainfall 82mm 46.6mm

Highest 20 minutes rainfall 42mm 38.8mm

Most Extreme one day rainfall

occurrence

243mm 68mm

Sources: Dickhaut (2015), Okyere et.al (2012) and Morden Ghana (n.d)

Figure 1: Annual precipitation data for Accra for 6 statistical periods Source: Waylen & Owusu, 2013


From the table, it was observed that the highest daily precipitation in Accra was recorded in 1995.

The amount of rainfall received during this period was about 243 mm, which is about 3.5 times of the

most extreme daily rainfall event recorded of about 68mm in 1994 for Hamburg. In Accra, about 82

mm of rainfall was received within one hour in 1995 (modern Ghana, n.d) compared to Hamburg’s

value, which is relatively lower. Accra and Hamburg’s 20 minutes precipitation were recorded to be

42mm and 38mm respectively. From these figures compared, it can be seen that Accra has received

higher precipitation amounts than Hamburg. A comparison between extreme precipitation

occurrences between Accra and Hamburg is show in Table 1.

As rainfall is one of the major causes of flooding in Accra, it is important to identify the trend of

rainfall and make some meaningful projections in order to put in place measures to reduce impacts of

flooding. Table 2 presented by Kwaku and Dave (2007) as cited by Amoako & Boamah (2014, p. 7)

gives a projection of the return periods of rainfall intensity in Accra.

Table 2: Projected annual 1day, 2 – 5 consecutive days’ maximum rainfall for Accra

Source: Adopted from Kwaku & Duke (2007)

The table presented shows that a maximum of 84.04mm, 91.60mm, 100.40mm, 105.67mm and

109.47 mm of rainfall amounts can be received on days 1,2,3,4 and 5 respectively after every 2 years.

In the same way, maximum amount of rainfall of 230.97mm, 240.49mm, 272.77mm, 292.07mm and

296.54 mm can be received on days 1,2,3,4 and 5 respectively after every 100 years. At the end of

their study, they came out with the conclusion that a period from 2 to 10 years return period is enough

for the “natural soil, water conservation measures, construction of dams and storm water management

to take place”.

Inter-tropical convergence zone

Rainfall patterns in Ghana and for that matter Accra is brought about by the movement of the Inter-

Tropical Convergence Zone (ITCZ). The harmattan wind (North East Trade Winds), which is dry, hot

and dusty, moves from the Sahara and later comes into contact with the cool and most air (South

West Monsoon Winds) from the Atlantic Coast (Kankam-Yeboah, Dapaah-Soalwam, Nishigaki, &

Komatsu, 2003). During the months from December to February, the ITCZ moves along the Gulf of

Guinea and brings about harmattan in all parts of the country and between March and November; it

shifts significantly and moves across Ghana (Kankam-Yeboah, Dapaah-Soalwam, Nishigaki, &

Komatsu, 2003). The ITCZ moves along the southern areas along the coast two times and it is

because of this movement that the coastal areas in Ghana receive two rainfall seasons.

2.2. Demographics

Population

According to the 2010 population census, out of the region’s total population of about 4 million

inhabitants (GhanaStatisticalService, 2012), approximately 2.7 to 3 million of them live within the


city of Accra (Amoako & Boamah, 2012) as at 2012. The statistics from the statistical report showed

that more than 90 percent of the region’s population is urban with the remaining being rural.

Age and sex distribution

The city as well as the region is made up of youthful population with the average age of the region’s

population is estimated to be 26 years and has more female population than male (GSS, 2012). It is

also estimated that about 51 percent of Accra’s population is female with the remaining 49 percent

being male (AMA, 2006).

Wealth distribution

There exists a high level of discrepancy in wealth distribution among the population of Accra even

though Adank, Darteh, Moriarty, Osei-Tutu, Assan, & Rooijen (2011) report that; more than 70

percent of Accra’s population is estimated to be non poor. This value gives a general impression that

Accra’s population is generally rich even though a significant number of poor populations exist.

2.3. Urbanism

Rapid growth

Over the past years, the city has been transformed as a result of increasing population and

urbanization. The city of Accra was previously just the area known as the Accra Metropolitan

Assembly (AMA). According to Adank, Darteh, Moriarty, Osei-Tutu, Assan, & Rooijen (2011), as at

the year 2002, the city Accra had developed and expanded outwards to include the “the Ledzekuku-

Krowor Municipal Area (previously part of AMA), the Tema Metropolitan Area (TMA), the

Ashaiman Municipal Area (previously part of TMA), the Ga East Municipal Areas, the Ga West

Municipal Area and the Ga South Municipal Area (formerly part of Ga West)” as shown in figure 2.

Figure 2: Urban growth of Accra from 1985 – 2002 Source: (Adank, Darteh, Moriarty, Osei-Tutu, Assan, &

Rooijen, 2011)

Informal settlement

The city is said to be the fastest growing city in Ghana having a population of about approximately 3

million inhabitants (Amoako & Boamah, 2014) and an annual growth rate of about 3.1 per cent

(Asumadu, 2015). The city currently covers a total land area of about (1,261 km2) as already


mentioned. This fast growing nature of the city is attributed to the fact that the city serves as the

administrative, political and commercial hub of Ghana.

Over the past decades, the city of Accra has experienced the influx of migrants who come normally in

search of jobs. This influx coupled with weak building regulations have led to improper and poor

building structures in most of the areas. These are the places within the region which have developed

to become slums and the informal settlements. Protected and ecologically sensitive areas have been

converted into places of residences. According to Okyere et. al (2012), the number of people per

kilometer square increased from 79 to 103 persons in the year 2010. It is therefore evident that this

increase in the population is likely to have exerted excess pressure on the existing infrastructure as the

population increases.

3. Storm Water

Within the last decades, Accra has experienced a number of periodic floods and during this time, a

number of lives and properties have been affected. This same situation persists every year when the

country experiences rainfall. In such a situation, it is prudent to evaluate the current system and

develop measures to minimize the impact of flood on life and property (Asumadu, 2015).

The city of Accra has been experiencing successive floods over the past decades. Nyarko (2000) as

cited by Okyere et. al (2012) stated that more than 40 percent of the area of Accra lies in the high and

the very high risk zones with only a small portion not affected.

Figure 3: Representing the various basins in Accra

From Figure 4 it can be observed that of the various storm water infrastructure that exists within

Accra, there are a number of partially lined drainage pipes, which include Chemu, Odaw, Kpeshie

and the Songo drains. The drainages are designed for heavy rainfall events that happen one time after

every 25 years (Adank, Darteh, Moriarty, Osei-Tutu, Assan, & Rooijen, 2011). The artificial

drainages mostly allow fast discharge of storm water (Nyarko, 2000) into the lagoons before they are

finally discharged into the ocean.


From all the catchment areas, the Sakumo II basin has the highest peak run off of about 3230 m3/s

which is followed by the Korle basin having a peak run off of about 2032 m3/s with the Mokwe-

Songo basin having the lowest peak run off of about 218 m3/s. The run-off is dependent on factors

such as the size of the basin, the amount of rainfall, the storage coefficient and the coefficient of run-

off. According to (Adank, Darteh, Moriarty, Osei-Tutu, Assan, & Rooijen, 2011), the run-off

coefficient for Accra lies between 0.7 and 0.95 and is estimated to increase as the rate of urbanization

increases.

Figure 4: Schematic of drainage system in Accra, Ghana

This indicates that Accra’s problem of storm water is and will still remain a challenge for the city to

deal with if nothing is done about the current rate of urbanization. There is however an increasing

number of areas situated around the catchment areas which are liable to flooding in case of any storm

water event. Figure 4 also includes the flood risk map of Accra and this flood risk map categories the

area into high flood risk area and low flood risk area. From this flood risk map, it was observed that

the areas located around the Sakumo II basin are the areas that are most prone to flooding even

though the entire area is generally low lying and prone to flooding. It is however interesting to

observe the nature of development around these flood prone areas. Most of the areas situated within

the catchments are built up and paved areas that reduces the areas ability for water retention but on

the other hand increases surface run off.

Buildings are also constructed along waterways, preventing the free flow of water. The number of

drainage systems is inadequate and the few drainage systems are in most cases chocked with waste.

These are some factors that add up to the increased frequency of flooding in Accra. As the city keeps

expanding, the sealing of the ground is increasing as well and the problem of flooding will become

increasingly exacerbated as permeable land area is lost (Adank, Darteh, Moriarty, Osei-Tutu, Assan,

& Rooijen, 2011).


Aside the negative effects rainfall has on Accra; there is as a major benefit that some people of the

city gain from it. The most important use of the rainfall in Accra is for rural farmers for agricultural

purposes. Agriculture activity could be beneficial if properly practiced since these areas could reduce

surface run-off during storm events.

3.1. Precipitation Events

From the mid 1950’s to 2015, properties valued more than GH¢300 billion have been destroyed by

flooding while a lot more lives have been affected during and after the various flood events whiles

others have also been displaced from their homes as a result (Asumadu, 2015). Floods form a portion

of the natural hazards that occur in Ghana aside drought, earthquake and bush fires. Among the

various occurrences of natural hazards reported in Ghana, floods have occurred most and have killed

more than the other natural hazards.

Figure 5: Return periods for precipitation events in Accra, Ghana

3.2. Causes of Flooding in Ghana

Most of Accra’s drains that connect directly to the lagoons are left uncovered, leaving the system

vulnerable to waste pollution. The drainage systems mostly get chocked by the plastic non degradable

waste which makes flow of water almost impossible. Inadequate drainage systems together with

dumping of waste into water bodies are part of the causes of the seasonal flooding in Accra.

The Problem of Waste Management

Accra’s nature of growth and urbanization has made sanitation a huge problem to deal with as it is

witnessed to be one of the major causes of flooding in Ghana. The Accra Municipal Assembly is

managing waste in Accra. The management includes the collection of the waste as well as its

disposal. The waste is dumped around the area of the Odaw River (UNEP, 2011). The collection of

waste in Accra was privatized at the end on the 1990s. The majority of the city is serviced by one

waste collection company Zoomlion (Thompson, 2013)


Table 3: Historical rainfall events in Accra

Date Amount of daily

Precipitation (mm)

Comments

1955 The first significant flood recorded in Accra

27th June, 1960 98

29th September, 1963 96

22nd

June, 1973 175

14th July, 1991 157

4th July, 1995 243 The city received the highest flood event in 49 years.

The number of deaths was recorded to be about 30 and

properties worth about 50 billion old Ghana cedis lost

(Danquah, 2013).

27th June, 2001 81 11 lives were claimed and 100,000 of the population

homeless. Several properties damaged (Amoako, 2014).

9th June, 2002 123

26th March, 2007 59

25th October, 2011 157 14 people killed and 17,000 people displaced (Okyere,

2012).

3rd

July, 2015 263 35 settlements were affected, 9,200 people were

affected and 150 lives were claimed (UNCT Ghana,

2015).

Accra has a number of informal settlements that have

developed in most of the flood prone areas and these

informal settlements lack waste management. According to

Amoako and Boamah (2014), more than 90 percent of the

flood prone areas are made up of informal settlements. The

increase urban growth has, come along with the increase in

waste generation which the city of Accra has not been able

to deal with. The high cost charged for waste management

prevents people from having access to proper waste

collection methods, which in turn encourages the urban

poor to poorly dispose off their waste. Most of these

informal settlements are haphazardly built which makes

accessibility into these areas difficult. This is a fact that

makes most areas here inaccessible by waste collection

trucks. Not all the areas within Accra are easily accessible

and as a fact, there is the difficulty of proper collection of

waste to the dumpsites. This problem of poor accessibility

is typical of areas located the Odaw river and the Korle

lagoon (UNEP, 2011). Solid waste management is one of

the most difficult problems the city has been forced to

handle. According to Amoako & Boamah (2014), the

principal causes of flooding in Accra includes the nature of

rainfall, impervious surfaces created as a result of increased

Figure 6: Waste-clogged drains


urbanisation, poor waste management, insufficient drainage systems, poor urban planning and

informal settlement development.

3.3. Recent Projects

Urban Environmental Sanitation Project

The Urban Environmental Sanitation Project was put in place because sanitation and waste

management were identified to be environmental issues that need quick attention. The urban

Environmental Sanitation Project was a project not just related to sanitation but flood management

and protection. The main idea behind this project was to provide the poor with access to urban

services as well as other urban development. Institution building, pollution management and

environmental health were also matters of concern (UNEP, 2004).

The project started in 1994 under the Ghanaian Ministry of Finance and Government and the Ministry

of Local Government and Rural Development. Other partners included the Nordic Development Fund

(NDF), VNG and the Agence francaise de Developpement (AFD).

The Odaw drainage pipe that travels through the heart of Accra was one of the major targets for this

project, with subsidiary projects focused on the Chemu West, Osu Klottey and Kpeshie drainage

canals (UNEP, 2004). Focus was on these areas because of the basins high contamination level. The

project was in five different categories. The first was related to storm water drainage improvement

while the other four were towards sanitation and solid waste management.

In Accra, the project related to storm water was to dredge and reconstruct the Odaw drainage (7

kilometers), which is one of the city’s principal drainage paths. The project also aimed to reconstruct

a number of other minor drains to serve 13 neighborhoods (UNEP, 2004). However, the Odaw project

changed a little bit since the budget kept increasing and as a result, just a part of the Odaw channel

was reconstructed. The initial design was to construct an “earth lined trapezoidal channel to a

concrete lined trapezoidal channel and finally to a reinforced concrete rectangular design” (UNEP,

2004). The reason for the changes in the design was to conserve enough space and to ensure that the

project did not affect (through relocation) the population around the project area. This phase of the

project was completed by the end of 2004. The drain was designed to withstand once in 25 years

rainwater events.

It was reported at the end of this project that the project’s aim was achieved by reducing the impact of

flooding on the low-income group living in the low lying and highly densified areas of Accra.

According the report from UNEP (2004), it was made clear that at the end of the project, the number,

intensity and the length of flooding events reduced considerably.

Odaw Drainage Improvement works

The Odaw Drainage Improvement works

project was an extension of the Odaw

drainage project under the Urban

Environmental Sanitation Project of Ghana.

The project continued again from 2004 to

2007 which was still under the Ministry of

Local Government, Rural Development and

Environment. The estimated budget for the

project was approximately 16 million Euros

and was constructed by a company from the


Netherlands known as the BAM International bv. The principal aim of the Odaw Drainage

Improvement works was to alleviate flooding and to reconstruct the drainage into a rectangular or

trapezoidal shape in order that it could stand flood events that occur once in every 25 years (BAM

International, 2009). The Odaw drainage was lined and was about 3.4 kilometers in length, 23 meters

in width and a depth of about 5 meters.

4. Flowing Water

Accra has various water bodies that flow through it. Two main rivers that can be mentioned in Accra

are the Odaw and Onyasia rivers. The main source of Accra’s supply of water is the Weija Dam,

which is located on the Densu River. The description of flowing water in Accra will not be complete

if the existing lagoons are not taken into account. The Korle lagoon is one of the city’s main and the

world’s most popular lagoon. However, a number of rural populations depend on rainfall and on these

flowing waters for their agricultural activities. Detailed description of flowing water in Accra is

explained below.

4.1. Hydrological Features

Accra has been partitioned into four main

catchment areas, which are Korle-Odaw catchment,

Densu River catchment, Kpeshie catchment and

Songo-Mokwe catchment (UNEP, 2011) even

though other smaller ones do exist as shown in

figure 1. These catchment areas are made up of

other rivers, which are either partly or not lined.

The Korle-Odaw is the biggest catchment of all

these catchments in Accra and the river together

with its tributaries within this catchment area

normally experiencing the greatest impact during

storm water events. According to Baffour (n.d),

Odaw is “centre most” basin that has a lot of water

flowing through it during the rainy periods. The

Odaw River flows through a natural drainage channel where it later empties itself in the Korle lagoon,

which is extremely polluted from urban and industrial wastes dumping. The storm water finally enters

Figure 7: Odaw Drainage Improvement Works Source: (BAM, 2009)


the sea. This channel of storm water through natural drainage systems to the sea is the most common

system most storm water drainage systems in Ghana follow. An example of this can be seen in the

figure 4.

4.2. Current System

The Korle lagoon will be used as a case study in this paper since it has received lot of attention on the

nation and global scale.

Overview of the Korle Lagoon

The Korle lagoon located along the coast of Ghana in past used to be a wetland that supported the

lives of various kinds of species. Currently, it is named to be one of the most polluted water bodies

existing in the world (Boadi & Kuitunen, 2002). It is one of the main channels for most of Accra’s

storm water discharge and it is directly connected to the sea. According to (DailyGuide, 2012), it

occupies a total surface area of about 0.6 km2 and serves a total catchment area of approximately 400

km2. The Odaw drain is one of the major drains which have one of the fastest discharges as seen in

table 4. The largest basin in terms of area is the middle Sakumo (155 km2) and also has the fastest

discharge (1825 m3/sec).

Table 4: Total discharge of basins within the study Area Sources: (Nyarko, 2002)

Figure 8: a. catchment areas, b. discharge rates, and c. runoff concentrations in Accra Sources: (Nyarko, 2002)


The problem that exists is that with these basins is that, despite the large nature of the Odaw and

Middle Sakumo basins, they normally over flow their banks during the slightest rain events as a result

of the pollution by the low income settlement inhabitants and industrial waste discharges. The Korle

lagoon is identified to have lost its primary role in improving water quality as it formerly use to help

remove sediments, nutrients and other harmful substances. It currently supports almost no ecosystem

as a result of the pollutants it has accumulated over the past years. According to (Boadi & Kuitunen,

2002), it has been found out that the lagoon’s main source of pollution includes sewage and garbage,

which are made up of about 70 to 80 percent organic matter. It is again estimated by (Boadi &

Kuitunen, 2002) that the Biochemical Oxygen Demand (BOD) is about 10500 kg day−1 and comes

mainly from the informal settlements living around the Korle lagoon and the Odaw river.

Current policies or programs to protect the water

Over the past years, there have been supports by donor agencies to improve sanitation in order to

protect the water bodies. The KLERP was one major project supported by BADEA/Kuwati

Fund/OPEC. According to OCIN (2005), reviews from the program indicated that, there were

inadequate facilities in terms of space. The only option was therefore to extend the water borne

sewage to possible areas to minimize the impact of pollution on water bodies. During the Accra

Waste Project (AWP) and the KLERP, fund was given to fix the treatment plant in order to reduce the

amount of untreated waste discharge into the lagoon. Less than 10 percent of the waste treatment

plants in Accra are operational (AMA, 2014). From this point, it can be concluded that the program

might have not fully achieved its aim in terms of untreated waste discharge into the water bodies.


KLERP (Korle Lagoon Ecological Restoration Project)

The project started in the year 2000 has received funding from international bodies including the

OPEC fund for International Development and the Arab bank for Economic Development in Africa.

The KLERP was part of the city’s sustainability projects to restore the ecology of the lagoon even

though it also aimed at improving Accra’s drainage and sanitation problems. It focused both on the

Korle lagoon and the Odaw River since the lagoon receives lot of pollutants from the river. The

project was divided into four main phases. During the first phase, the lagoon was dredged to remove

the unwanted sediments. It also aimed at removing swamps to reduce flooding. The second phase

dealt with the construction of inceptors. The third phase was also geared towards dredging of the

lagoon and the final phase was to execute the necessary environmental impact assessment.

The details of each phase are explained in table 5.

Table 5: Phases of the Korle Lagoon Ecological Restoration Project

Phase 1 Phase 2 Phase 3 Phase 4

Dredging of the

lagoon

Construction of an

inceptor

Sediment removal

and re-dredging of

the lagoons

Design, supervise

and construct bulk

services including

roads, water , sewer,

storm water,

drainage

Creation of storm

water canals

Construction of a

pump station

Sediment removal in

the canals and drains

Execution of the

require


Environmental

Impact assessment

Removal of swamps

to reduce flooding

Outfall install works Fencing and

beautification works

Creation of green

areas

Infrastructure works

Source: (PMI, n.d)

KLERP: Source: (PMI, n.d)

Figure 9: Odaw River Dredging as part of the city’s sustainability project towards the Korle Lagoon Restoration


Evaluation of the project

Report from (DailyGuide, 2012) indicated that, there had been commitment on the part of the

informal settlements in making the project successful. It was again stated that the authorities of the

city ordered a 50 meter buffer distance around the lagoon, therefore, some settlements needed to be

demolished.

5. Waste Water

5.1. Existing Infrastructure and Trends

“Over the years there has been a lack of political will in Ghana to implement basic sanitation and this

is reflected in the amount of resources allocated for wastewater management, the main reason being

the phenomenal investment in the physical infrastructure of wastewater treatment plants. This coupled

with rapid industrialization and urbanization have generated increasing amount of [untreated]

wastewater, resulting in environmental deterioration and frequent outbreak of water-borne diseases”

(Awuah & Abrokwa, 2008).

With a population of approximately 3 million, it is estimated that Accra produces roughly 80 million

liters of wastewater per day (Lydecker & Drechsel, 2010). A nationwide assessment of the state of

wastewater and fecal sludge in Ghana by the International Water Management Institute (IWMI)

(2009) concluded that there were 30 wastewater plants in Accra, with only 10 percent operating as

designed. The majority of these plants service small communities and institution, such as hospitals,

universities and the military base indicating that the wastewater treatment system in Accra is largely

decentralized. Even if working properly, the combined capacity of these plants is only sufficient to

service 5-7 percent of Accra’s total population (Obuobie et al., 2006). The IWMI estimated that

nearly 90 percent of all wastewater generated in Accra is discharged directly into the river basins,

without treatment, and most of this pollution ends up in the Korle Lagoon.

According to the Accra Metropolitan Assembly (AMA) (2014) “Accra currently has a sewerage

system that covers only 15% of the city, but it is in complete state of disrepair giving rise to serious

environmental pollution and degradation and the concrete sewers are completely eroded at certain

sections of the network. It was laid about four decades ago. This situation calls for a complete

overhaul of the system.”

Only 30 percent of the houses in Accra have toilets that flush with water and only 20 percent have

running water. The majority of the other 70 percent of the population are serviced by public toilets,

which are considered “accessible” at a rate of one toilet per ten people (Thompson, 2013). The public

toilets are open-pit latrines that are emptied by a vacuum cess truck often only when they become full

or backed up. By design these trucks should transport the fecal sludge to a treatment facility, but due

to the incapacity and debilitated state of the current system they often empty directly into the rivers

(Kathijotes, 2012). Worst still, open defecation is commonly practiced as the public toilets are

insufficient to serve the population and often highly unsanitary and unsafe, especially during the night

hours and for women. The occurrence of high concentrations of human feces on the landscape and all

throughout the open and flowing water system results in extreme human health risks. Mosquitos favor

such conditions and Malaria is the leading cause of death in Accra. The open and flowing waters are

a primary source of drinking water for many of the city’s informal inhabitants and the only irrigation

source for the 750 ha of urban agricultural land informally worked around the city. Hygiene related

diarrhea claims over 20,300 lives every year in the city (Thompson, 2013)(Obuobie et al., 2006).



The James Town Upflow Anaerobic Sludge Blanket (UASB) was designed by a Chinese engineering

firm and constructed in 2000. The plant operates as an anaerobic microbial digester with a design

capacity of 16,120,000 liters of wastewater per day. At a per capita rate of 50 liters of wastewater per

person per day, this system was designed to 322,400 people living in the surrounding area, or 10

percent of the city’s population and to offer greatly needed reduction of direct effluent discharge into

the Korle Lagoon, which the plant is located adjacent to, 0.5 km from the Gulf of Guinean.

The plant was an integral part of the Accra Waste Project, one of the first of a series of multi-million

dollar international investment projects aimed at improving sanitation and alleviating flooding in

Accra. The plant was “designed and built on sustainable principles including optimized process

efficiency for tropical conditions, minimizing the consumption of electricity and using appropriate

technology” (Awauh & Abrokwa, 2008).

The Jamestown UASB is relatively simple technology, but considered robust for an African nation.

As shown in Figure 10, the influent is sent through a series of nine stages requiring 4 to 6 hours of

retention time for treatment and an additional 9 hours retention time for liquid effluent and 60 days

drying period for sludge effluent (Awauh & Abrokwa, 2008).

Screening – First the influent coming from the Central Accra Pumping Station (CAPS), where all

collected sewage from the metropolitan convenes, is pumped through a series of course-grit screens to

ensure uniformity of substrate before it enters the reactor.

Primary, Secondary and Tertiary Distribution Boxes – Next, the influent is pumped though a series of

three distribution boxes that ensure an even proportional flow to the reactors. The tertiary distribution

box feeds into the bottom of the UASB reactors.

Anaerobic Primary Treatment Stage (UASB reactors) – The UASB reactors are maintained at a

temperature of 29°C ± 2 and operated in the absence of oxygen (anaerobic). The wastewater flows

from the bottom of the reactor “upward through a sludge blanket composed of biologically formed

granules” (Awauh & Abrokwa, 2008). The microbes digest the organic material releasing gases,

predominately methane and carbon dioxide, which cause internal circulation and keep the reactor

Figure 10: Systematic diagram of the UASB reactor wastewater treatment plant Source: (Awauh & Abrokwa, 2008)


operating evenly and encourages formation and maintenance of the biological granules with minimal

energy inputs. The free gas particles rise to the top of the chamber where it is collected and used for

energy production.

Aerobic Fixed Growth Reactor (Trickling Filters) – After passing through the UASB reactor the

effluent flows by force of gravity to the trickling filters where further biological treatment takes place.

Final Settling Tanks – The effluent should be allowed to settle for no less than 9 hours in the final

settling tank where further organic reduction is achieved through a series of fine filters before the

liquid effluent is discharged into the Korle Lagoon.

Sludge Thickeners – The remaining solids are pumped into the sludge thickeners for further settling

and drainage for a period no less than 60 days for effective pathogenic treatment.

Sludge Drying Beds (24) – Final treatment of solid effluent is dislodged from the sludge thickeners

and spread across 24 drying beds to lie and back in the sun for a period of 3-6 months allowing UV

radiation to further destroy pathogens to an appropriate level of 10-100 no./100ml for use in

agriculture. Liquids from the effluent are drained through sand filters and collected in a system of

under-drains.

The effectiveness of the UASB treatment process is detailed by common parameters used to measure

water quality and in comparison with EPA Ghana 2000 guidelines in Table 6. The reader should

observe two trends represented in this table. First, there is no significant improvement of water

Source: (Awauh & Abrokwa, 2008)

Table 6: Characteristics of sewage at different treatment stages in comparison with EPA Ghana 2000 Guidelines


quality from the final settling tank stage to the final effluent values (post drying beds), even for fecal

coliform, which is the parameter to be treated in this phase. Second, the plant has worrisomely low

efficiency values in 6 of the 11 measured parameters: ammonia-nitrogen, nitrate-nitrogen, heavy

metals, phosphate-phosphorus and fecal coliform. Please note, fecal coliform removal is rated at

99.9% efficiency, but the value is more than double of the acceptable limits set by the EPA Ghana

2000 guidelines.

5.3. Performance Overview

Sadly, the Jamestown UASB wastewater treatment plant has a track record similar to all of the other

large infrastructure projects that have been implemented in Accra over the past two decades. It is

reported that the plant was completely out of operation by 2004. During this time sewage collected at

the Central Accra Pumping Station was directed to an emergency discharge outlet into the Gulf of

Guinean. Later investigation determined that the emergency outlet piping had cracked in multiple

locations and all untreated effluent was leaking directly into the Korle Lagoon, frustratingly at the

height of the Korle Lagoon Restoration Project thwarting all attempts to improve the ecological

capacity and sanitation quality of the lagoon (Lydecker & Drechsel, 2010). At the time of the

performance evaluation conducted by Awauh & Abrokwa (2008) 3 of the 6 reactor chambers were in

proper working order. Further, their analysis identified that the plant was operating below design

capacity and efficiency rating because (1) employees had a lack of technical training, (2) plant

operators had not been successful in attempts to acquire operation manuals for the plant by the

engineers, and (3) there was no one employed on staff with the technical training to oversee

operations of such an intricate system. No literature was found evaluating the plant’s performance

post 2008.

6. Conclusions and Recommendations

It is clear that Accra, as a whole, is unfortunately well below an acceptable level of public service and

sanitation, leading to poor health and general social degradation. This report should have made clear

the myriad of infrastructural problems that have resulted in a degraded urban environment and

highlighted the capacity of one deficiency to amplify other deficiencies.

In this section, we will focus on integrated and holistic methods that could be employed in Accra to

synergistically improve the state of water in the city, ultimately improving the environmental, human

health, social and economic capacity of the area.

During this section the reader should keep in mind that Accra has been the recipient of hundreds of

millions of dollars from international investment banks for massive infrastructure projects to improve

the state of water in Accra. These include The Accra Waste Project (AWP) (1996-2002), Korle

Lagoon Environmental Restoration Project (KLERP) (1995-2005), Urban Environmental Sanitation

Projects (UESPI-1996-2001 and UESPII-2003-2015) and the Teshie Faecal Treatment Plant (1194-

1995). However, despite two decades of construction, nearly a billion in loaned funds and ample

design, construction and training support from European, American and Chinese firms, Accra is still

subject to annual catastrophic floods and toxic water quality. Future solutions must analyze the failure

of these previous projects and encourage solutions that match the existing technical, social,

economical and educational capacity of the administration and available workforce in Accra.


6.1. Solid Waste

It is the strong opinion of the authors that a desirable, productive and healthy environment in Accra is

not possible without first managing solid waste. A report concluded in 2014 by the Accra

Metropolitan Assembly estimates that 2,200 tons of garbage is generated daily, but the existing waste

management system only has the capacity to manage 1,500 tons per day. The remaining 700 tons

accumulate in the natural environment – every day – to provide breeding environments to mosquitos,

the prime vector of Malaria, and to clog essential storm water drainage infrastructure.

Currently, approximately 20% of households in Accra are serviced by household waste collection,

and these are all high-income areas (Thompson, 2010). The remaining 80% are asked to dispose of

waste at Central Collection Containers (CCC) free of charge.1 This solution is seemingly non-

effective as the accumulated litter is evident. Partially this is due to the backlog of 700 tons of waste

per day that the AMA lacks the capacity to manage, but it is notable that these backlogs are

concentrated in the poorest and most under-developed and informal areas of the city, which have

densely encroached upon the banks of the rivers and storm drains over time (Thomas, 2010). AMA

(2014) claims this is nearly unavoidable as the road infrastructure (or lack there of) prohibits regular

access to such communities with massive waste vehicles. Thomas has offered an interesting

observation that may lead to tangible, place-specific solutions finding.

“It seems poignantly incongruous that there exist simultaneously so many people seeking work and

also so much potential for physical labor to raise basic environmental health standards. Labor is one

of the most available inputs in Ghana’s waste management sector. It is certainly more readily

available than capital stock and imported technologies.”

One possible solution is to have segregated waste streams collected separately directly from people’s

homes with small carts that can be pushed by hand or pulled by bike. Separating the waste streams

would result in a drastic reduction of material sent to open dumpsites2 as 65% of the waste generated

in Accra is organic, and could be composted (Thompson, 2013). A waste characterization study and

market analysis are needed to determine if such a system could be self financing based on revenues

from recovered commodities, such as metals, plastics and compost material for agriculture. If the

system cannot sustain itself, AMA could consider imposing a manufacturing fee for hard to handle

materials, such as Styrofoam and plastic films. Such an analysis should also consider saved expenses

related to avoided flood damages by preventing solid waste from clogging storm drains.

6.2. Urban Agriculture

Lydecker & Drechsel (2010) have proposed that urban agriculture is a viable option to mitigate

flooding, littering, erosion, informal settlement development in buffer zones, and reduce human waste

discharge into the open waters of Accra. The study found that lands that are currently being used for

urban agriculture are clean from litter, informal developments and are not used as sites for open

defecation or privy dumping as the general population show a level of respect to the farmers as the

authority of the land, although the farmers are typically squatting on the land themselves.

1 AMA attempted to enact a pay-as-you-throw scheme to fund the public collection sites, but the initiative

resulted in greater accumulation of pollution in the surrounding areas as residents avoided the CCCs in order to

avoid the associated dumping fee. 2 There are no engineered landfills in Accra. Waste is piled in old rock quarries, abandoned mines and into

naturally occurring holes where lechate and emissions are uncontrolled and unmonitored (Thompson, 2013).


Collectively, 931 hectares, or nearly 7 percent of the total land area of Accra is being used for urban

agriculture, providing subsidence to 80,000 farmers (AMA, 2014).3 The AMA could grant temporary

rights to urban farmers to cultivate lands around open drains and rivers. In addition to the previously

mentioned benefits, organic matter accumulation from compost applied to the site and the grasp of

roots from vascular plants, especially maize, would significantly reduce runoff into the drains and

rivers, which is sited as the second leading cause of flooding, after waste accumulation.

6.3. Storm and Flowing Waters

A continuous history of massive drainage projects, such as the Odaw Drainage Improvement Project

with storm drains 5 meters deep and 8 meters wide, followed by catastrophic flooding events as

recent as May 2015 should highlight that building ever bigger and lined drainage systems does not

seem to be the appropriate solution for Accra. As flooding often starts at the overwhelmed Korle

Lagoon and then backs up into the city, the primary focus should be on restoring the lagoon, which is

in progress, and retaining storm waters upriver by providing opportunities for absorption into the

ground. Lined drainage systems are not a means of achieving retention. Portions of the drainage

system that are not yet lined should receive a partial covering of various rock sizes along the bed of

the drains to prevent runoff and the build-up of sedimentation, and to eventually offer habitat to

species that can prosper once the ecological capacity has been restored via other measures (Dickhaut,

2015).

As the rivers are – terrifyingly – a source of drinking water for many and for irrigation, water cisterns

sufficient in quantity to meet the needs of the 80 percent of the population lacking access to running

water would offer substantial relief to the volumes of water entering the drainage system during

heavy rain events if strategically placed (AMA, 2014). In depth spatial analysis of the informal

settlements and drainage basins is needed to quantify the potential volume of water that could be

stored in this fashion, but the AMA admits that the two existing waterworks servicing Accra leave a

daily short fall in the demanded drinking water of 130,000 m3.4

Possibly the most vital component for mitigating flooding risk in Accra is by preventing litter build-

up in the drainage system. Referring back to the conundrum of environmental degradation and vast

unemployment articulated by Thomas (2010), a large workforce should be employed to maintain the

drainage systems as designed by manually clearing waste and removing accumulated sedimentation.

The cost of this system should be calculated as saved damages from proven flooding risk.

6.4. Waste Water

There are two complementary approaches that could be taken in unison to improve the current system

of wastewater management in Accra, improvement of the centralized wastewater treatment facilities,

and development of viable treatment options for septic sludge from household pit latrines and public

toilets. First, the existing sewage system must be repaired and all existing wastewater treatment

facilities brought up to operational capacity. Improvements will only be sustained with adequate

training of personnel including regular continuing education workshops and monitoring of

performance (Ewag – Sandec, 2006). However, this will cover no more (if operating at full capacity,

which has not yet happened) than 30 percent of the daily wastewater generated (AMA, 2014).

3 One hectare is the equivalent of one-tenth of a square kilometer.

4 This value is suspiciously small as it reflects that only 24 percent of the daily sanitary water demand is not

met, as 80 percent of residences, both formal and informal, do not have running water (Thompson, 2013).


Septic tank emptying services were privatized in Accra in the late 1990s (Thomas, 2010). As the city

lacks sufficient capacity to treat the vast majority of wastewater-generated daily, a fee is imposed on

septic haulers to empty at wastewater treatment facilities. This cost is passed down to the customer

prohibiting families from building pit latrines and in lei use pots and buckets in the closets of their

homes, which they empty on the landscape or in the rivers. The AMA has attempted to thwart haulers

attempts to avoid disposal fees by illegal dumping through heavy fines and legal persecution, but the

AMA admits that its attempts have been futile (2014). Kathijotes (2010) documents numerous

effective projects implemented in developing countries using a “flux reversal” system, which pays

fecal sludge haulers a standard rate for every truckload emptied at an accredited facility.

Again, this circles back to the conundrum of having a dramatic lack in proper wastewater treatment

facilities. Lydecker & Drechsel (2010) in coordination with the International Water Management

Institute and Eawag-Sandec (2006) have conducted and reviewed numerous studies on the health

impacts of using human wastes as a compost material. They argue that the organic matter greatly

improves the holding capacity of the soil, preventing erosion – something that inorganic fertilizers do

not accomplish – and that systems have been proven to properly prepare the material. The authors

argue that systems have been proven to safely handle and measure the material by allowing it to settle

for one to two months in a tank in the sun, and then to spread the material in thin layers over a nylon

lining over the ground, to prevent percolation of contaminants into the soil, for 3-6 months, or until

the material measures nematode eggs at quantities at or below 3-8/g treated sludge (Xanthoulis &

Strauss, 1991) as modified from the World Health Organization’s (WHO) 1989 recommendation of 1

nematode egg/liter of treated wastewater used to irrigate vegetables at a rate of 2-3 tons of treated

sludge per hectare per year.

Frankly, their results are questionable as they submit that vegetables grown in human waste composts

have alarmingly high rates of pathogens, often measured by the WHO standard of helm eggs, and has

been attributed to 120,000 lost healthy life years (DALYS, disability adjusted life years) every year in

Ghana from the consumption of vegetables irrigated with wastewater. Further research is needed to

verify the safety of using human biosolids as a soil conditioner.

Conclusion

Ultimately, there are a multitude of small-scale, decentralized, low-tech solutions that could be

readily employed in Accra to greatly improve that state of water in the city. Identification of any

specific technology or system will require holistic and scrutinous research into the case-specific

characteristics, opportunities and limitations.

“An array of tools from which stakeholders can choose has been identified. They comprise

systematic planning based on stakeholder identification and their cooperation (integrated with

urban sanitation planning);

regulations on services provision and management procedures;

fee structuring and money fluxes (flux reversal!);

development of services to private entrepreneurs;

rules to secure a competitive market;

[case specific]appropriate treatment options;

securing markets [such as for biosolids, food waste and plastics].

Potential solutions suiting local conditions and needs should be further developed and tested in

pilot/demonstration projects. They should be monitored and evaluated in order to establish practical,

action-oriented recommendations complemented by capacity building programs “ (Kathijoles, 2012).


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managing at the same time too much and not enough water in accra, ghana

Leadership & Management