Chapter One:Introduction VOL1

From Ministry of Water DCOM Manual

1 Chapter One: Introduction

The preparation of this DCOM manual was preceded by an overview of five important global considerations of Water Supply and Sanitation prior to reviewing the water and sanitation sector in Tanzania. This was followed by an explanation of the rationale for the preparation of the 4th edition. The introductory chapter is concluded by presenting the organization of the manual as well as the purpose and content of this volume of the DCOM manual.

1.1 Global Consideration on Water Supply and Sanitation

1.1.1 Sustainable Development Goals (SDGs)

In 2015, world leaders convened at the United Nations Headquarters in New York and adopted the 2030 Agenda for Sustainable Development. Governments responded to the common development challenges then faced and to the changing world around them by uniting behind a truly forward-looking, yet urgent plan to end poverty and create shared prosperity on a healthy and peaceful planet. The central principle of Agenda 2030 is leaving no one behind in achieving the 17 SDGs through 169 targets.

The 2030 Agenda for Sustainable Development adopted at the UN Summit includes SDG 6 on Water and Sanitation and in December 2016, the United Nations General Assembly unanimously adopted the resolution “International Decade for Action-Water for Sustainable Development” (2018–2028) in support of the achievement of SDG 6 on water and sanitation and the related targets (United Nations, 2015). It should also be noted that, water and sanitation are at the heart of the Paris Agreement on climate change 2015 (UNFCC (2015).

Ensuring availability and sustainable management of water and sanitation for all has therefore been, for a long while, an important topic at the United Nations and is now turning this vision into a reality, through national leadership and global partnerships. Water and sanitation are at the core of sustainable development and the range of services they provide, underpin poverty reduction, economic growth and environmental sustainability. The world needs to transform the way it manages water resources and the way it delivers water and sanitation services for billions of people.

The designers and engineers, therefore, have the responsibility to support the Government of Tanzania in achieving the SDG 6, where population growth and rapid urbanisation have intensified demand for water and sanitation services beyond all past thresholds.

1.1.2 Climate Change and Resilience to Climate Change

Climate change is now recognized as one of the defining challenges for the 21st century. More frequent, intense and extreme weather events continue to result in higher incidences of floods and droughts around the planet. The ensuing adverse impacts of climate change on water and sanitation services constitute a serious threat to human health and overall development of nations. Ensuring optimal resilience of water and sanitation services in a globally changing climate context will continue to be crucial for maintaining the momentum of making progress in health and general socio-economic development. Climate variability is already a threat to the sustainability of water supplies and sanitation infrastructure.

Flood occurrences continue to cause shocks for affected populations and to challenge water and sanitation managers. In many places floods are likely to become more frequent with intensification of climate change, thus;

  • Floods can have catastrophic consequences for basic water and sanitation infrastructure. Such damage can take years to repair.
  • On a smaller scale, drinking-water infrastructure can be flooded and be put out of commission for days, weeks or months.
  • Where flooding of sanitation facilities occurs, there may not only be a break in services, but the resultant flooding may distribute human excreta and its attendant health risks across entire neighborhoods and communities.

Droughts occur unpredictably worldwide. In many places they are likely to become more frequent and more widespread with climate change. For example: Falling groundwater tables and reduced surface water flows can lead to wells drying up, extending distances that must be travelled to collect water, and increasing water source pollution. In response, drilling rigs, which would otherwise be used to increase access, may be redeployed to renew or replace out-of-service wells, slowing the actual progress in extending access.

Since climate change is likely to affect water sources and infrastructure in Tanzania, it must therefore be taken into consideration (i.e. ensure enhanced adaptation capacity) in design, operation and maintenance of water and sanitation infrastructure or projects. Globally, climate change studies are coordinated by the United Nations Framework Convention on Climate Change (UNFCCC) and the Inter-Governmental Panel on Climate Change (IPCC). Accordingly, designers should use the latest information, data and model predictions available and include statements on what measures, if any, have been allowed for in order to cope up with (or adapt to) climate change within the time frame of pertinent project design (i.e. design period)

1.1.3 Public Private Partnership in Water Supply and Sanitation Projects in Developing Countries

One of the key challenges faced by water authorities in Developing Countries (DC) is how best to manage service delivery obligations to rural communities. Even in decentralized sectors, water authorities may find it hard to provide services to remote rural communities. It is recognized that water user associations and/or local private operators may be best placed to provide services as they are close to the users. The majority of the agreements are currently in place in the short term (1 to 3 years) management or operation and maintenance contracts for existing systems that involve minimal investment from the private sector. One key issue that arises repeatedly though is how to effectively regulate and monitor performance of activities under these contracts.

Globally, activities undertaken in 2005 suggest that private participation in the water sector is entering a new phase. New private firm involvement is continuously focusing on smaller projects and bulk facilities. Contractual arrangements involving utilities are combining private operations with public financing and new players are entering the market.

In an infrastructure-intensive sector, improving access and service quality to meet the SDGs cannot be done without massive investment. Around the developing world, the water sector is chronically under-funded and inefficient in addition to giving low priority to sanitation. In this context, Public-Private Partnerships (PPPs) can be a mechanism (among others) to help Governments in funding the much needed investment and deploying technologies and efficiency that can improve the performance and financial sustainability of the water and sanitation sector.

Governments are currently using private firms in the water and sanitation sector increasingly to finance and operate bulk water supply and wastewater treatment. New technologies and innovations such as desalination and wastewater re-use are currently being increasingly introduced, where traditional water sources have become scarce. Utilities are drawing on specific expertise, such as Non-Revenue Water (NRW) reduction and pressure management, to promote efficiency and improvement of services. Private investors and providers are increasingly becoming local and regional, and so raising competition and pushing down charges.

Most utilities are increasingly turning to the private sector for turnkey solutions to the designing, building and operating water and wastewater treatment plants, and in some cases they also provide financing. With new technologies such as membrane filtration and in wastewater treatment; utilities have faced challenges in finding the capacity to operate and maintain these facilities and in selecting the most appropriate technology.
Where a utility has the funds or is seeking financing to develop water or wastewater treatment plants but wishes to draw on the private sector to Design, Build and Operate (DBO) a facility, then the DBO approach is used.

The International Financial Institutions (IFIs) are being asked to finance such approaches. In response, the WB has recently developed a suite of documents for DBO deployment in water and sanitation projects, including an initial selection document; a Request for Proposal (RFP) with DBO document based on The International Federation of Consulting Engineers (FIDIC), an acronym for its French name Fédération Internationale Des Ingénieurs-Conseils) Gold Book and a guidance note with guidance on when the DBO approach is appropriate and how to approach such projects; draft framework for Employer Requirements and draft Terms of Reference for Consultancy support to carry out the requisite studies and develop the documents (World Bank, 2010).

1.1.4 International Water Law

The URT is riparian to the following trans-boundary International River Basins: Congo River Basin, Kagera River Basin, Nile River Basin and Zambezi River Basin. These water sources are managed using international law on trans-boundary resources.

International law is a culture of communication that “constitutes a method of communicating claims, counter-claims, expectations and anticipations, as well as providing a framework for assisting and prioritizing such demands” (Shaw, 2008). International water law is the law of non-navigational uses of international watercourses.

In international water law, there are two substantive principles that ought to be taken into consideration when sharing international waters:

  • The principle of equitable utilization which is a more subtle version of the doctrine of absolute sovereign territory. It argues that a (nation) state has absolute rights to all water flowing through its territory.
  • The principle of no significant harm is the delicate version of the doctrine of both absolute riparian integrity (every riparian state is entitled to the natural flow of a river system crossing its borders) and historic rights (where every riparian state is entitled to water that is tied to a prior or existing use) (Wolf, 1999).

There are two relevant international water conventions for trans-boundary water cooperation. The 1997 Convention on the Law of the Non-navigational Uses of International Watercourses (i.e. UN Watercourses Convention, 1997), and the 1992 UNECE Convention on the Protection and Use of Trans-boundary Watercourses and International Lakes (i.e. UNECE Water Convention, 1992) which recently broadened its membership beyond the EU to a global audience. In March 2016, Water Convention became a global multilateral legal and Inter Governmental framework for trans-boundary water cooperation that is open to accession by all UN member states. The soft law of the SDGs provides further impetus to the management of trans-boundary water resources directly through Goal 6.5: Implement integrated water resources management at all levels, and through trans-boundary cooperation as appropriate, and indirectly through Goal 16: Promote peaceful and inclusive societies for sustainable development. In this case, the contribution of designers and engineers is in the provision of tools and information or data to support the needed decision-making.

The management of water resources that entails extraction of shared international water resources in the form of rivers, lakes, seas and oceans as sources are guided by International Conventions and/or Protocols that have to be subsequently ratified by respective national Parliaments before they become enforceable. Because Tanzania is a member of the EAC, SADC and the African Union, it has ratified a number of the conventions and/or protocols that are associated with water resources management and water supply and sanitation services. At an African level, Tanzania fully subscribes to the Agenda 2063 that ensures African development is guided by African experts to attain the aspirations of “The Africa that we want” with respect to water supply and sanitation services. Furthermore, as a member of the United Nations, Tanzania’s water supply and sanitation services are guided by the UN SDGs of 2015 as well as the UNFCCC (2015) as mentioned earlier on.

1.2 Development Agenda and Water and Sanitation Sector in Tanzania

The Tanzania Development Agenda includes the Tanzania Development Vision (TDV) 2025). The realization of TDV is carried out through Five Year Development Plans. Currently, the GoT is implementing the Second Five Year Development Plan (FYDP II), 2016/17 – 2020/21.

The Government adopted the TDV in the mid-1986s for socio-economic reforms and the same continues to be implemented to date. Better and improved water and sanitation services contribute to one of the attributes of Vision 2025, which is on high quality livelihood. Thus, the review and update of this manual better shapes the future in which water and sanitation services will be delivered to enhance the health and improved livelihoods of normal citizens who are a critical national labour force.

The FYDP II has integrated development frameworks of the first Five Year Development Plan (FYDP I, 2011/2012-2015/2016) and the National Strategy for Growth and Reduction of Poverty (NSGRP/MKUKUTA II, 2010/2011-2014/2015) further extended to 2015/2016 - 2019/2020. The FYDP II is built on three pillars of transformation: industrialization, human development, and implementation effectiveness, and is aligned to the relevant SDGs. Importantly, industrialization placeshigh demand on utility supplies e.g. energy and water, so subscribing on addressing the SDG Goals 6: on water and sanitation.

Chapter 4 of the FYDP II, sub-chapter 4.3.4 on Water Supply and Sanitation Services sets key targets by 2020: Access to safe water in rural areas, 85%; regional centres and Dar es Salaam, 95%. Proportion of rural households with improved sanitation facilities, 75%; regional centres, 50% and Dar es Salaam, 40%. Non-revenue water (NRW) for regional centres, 25%; for Dar es Salaam, 30%. The Key targets by 2025 are: Access to safe water in rural areas, 90%; regional centres and Dar es Salaam, 100%. Proportion of rural households with improved sanitation facilities, 85%; regional centres, 70% and Dar es Salaam, 60%. Non-revenue water (NRW) for regional centres, 20%; for Dar es Salaam, 25%. One of the tools towards achieving the key targets of water supply and sanitation is the effective application of the DCOM manual.

The Government has a comprehensive framework for sustainable development and management of water resources where there is an effective policy, legal and institutional framework. The water sector policy and strategy contains operational targets to be achieved in terms of coverage and timescale for improving water resources management, water supply and sanitation. The targets are reflected in the National Water Sector Development Strategy (NWSDS) of 2006. Based on the targets of the ruling party manifesto on water coverage for rural areas and urban areas are 85% and 95% by 2025, respectively which are also articulated in the WSDP.

In the context of water supply and sanitation services in Tanzania Mainland, the Water Supply and Sanitation Authorities (WSSAs), in collaboration with Rural Water Supply and Sanitation Agency (RUWASA), are responsible for management of water supply and sanitation services mostly in the urban, towns and rural areas as well as in areas that used to be managed by National Water Utilities. The water sector status report of 2017/18 has set water coverage targets of 95% for Dar es Salaam, 90% for other WSSAs and rural areas, 85%.

The Community Based Water Supply Organisations (CBWSOs) are the basic units responsible for management of water supply and sanitation services in rural areas under the overall coordination of RUWASA. The WSSAs are regulated by the Energy and Water Utilities Regulating Authority (EWURA), while CBWSOs are regulated by the RUWASA under the Ministry of Water that is in turn responsible for rural water supply and sanitation services in Tanzania. As part of the ongoing reforms in the MoW, a number of small WSSAs have been clustered with urban WSSAs leading to reduction of WSSAs from 130 to 71. RUWASA has been charged with the task of supervising the operations of 50 small town WSSAs in addition to the CBWSO managed projects.

The regulatory role of WSSAs is provided by the Energy and Water Utilities Regulatory Authority (EWURA) and to some extent by RUWASA. With regard to sanitation, the water sector status report 2017/18 has estimated an average coverage of sewerage systems to be 30% (2018) in urban areas. On sanitation achievements, the same report indicates that by 2018, safely managed sanitation was available to only 21.2% of the population compared to the target of 25%. When this is compared to the SDG target of 100% by 2030, it can be seen that Tanzania is lagging behind by far

1.2.1 National Water Policy

The National Water Policy (NAWAPO) of 2002 guides the management of the water sector in Tanzania with major emphasis being on the active participation of communities, the private sector and the local governments in protecting and conserving water sources, supplying water and management of water and sanitation infrastructure. Currently, the review of the NAWAPO is at fairly advanced stages.

The main objective of the National Water Policy of 2002 was to develop a comprehensive framework for sustainable development and management of the Nation’s water resources, in which an effective legal and institutional framework for its implementation was put in place. The policy aimed at ensuring that water beneficiaries participate fully in planning, construction, operation, maintenance and management of community based domestic water supply schemes. This policy sought to address cross-sectoral interests in water, watershed management and integrated and participatory approaches for water resources planning, development and management. Also, the policy laid a foundation for sustainable development and management of water resources in the changing roles of the Government from service provider to that of coordination, policy and guidelines formulation, and regulation. Other objectives of the water policy included: increasing the productivity and health of the population through the assurance of improved water supply and sanitation services to the water users and to identify and preserve water sources.

1.2.2 Legal and Institutional Framework for Water Supply and Sanitation

Basically, the water and sanitation sector is governed by two main broad legal frameworks namely:
I. Water Resource Management Act No.11 of 2009
II. Water Supply and Sanitation Act No. 5 of 2019.
In the institutional framework, there are several organs under the Ministry of Water, which coordinates water supply and sanitation delivery service: the Directorate of Program Preparation, Coordination and Delivery Unit (PCDU), Directorate of Water Resources Management, Basin Water Boards (BWBs), Directorate of Water Supply and Sanitation, Directorate of Water Quality Services, Rural Water Supply and Sanitation Agency (RUWASA) and Water Supply and Sanitation Authorities (WSSAs). Special attention is hereby paid to RUWASA as, in collaboration with respective regional or district authorities is responsible for planning and managing, and supervising the rural water supply and sanitation projects, including financial and procurement management, as well as monitoring and evaluation for contracting consultants and local service providers to assist with planning and implementation of the projects at the district level and in the communities.

Through implementation of WSDP I and II (up to 2019) projects, the role or participation of the beneficiaries in planning, construction, operation, maintenance and management of community based domestic water supply schemes was guaranteed in most of the implemented projects through establishments of COWSOs in every completed project that was given all the mandate of making sure the project is sustainable. Among the lessons learnt from the implementation of WSDP I & II projects was the need for engineers and consultants to use the MoW Design manuals in order to reduce or eliminate the many design flaws already observed.

However, according to the Water Supply and Sanitation Act No. 5 of 2019, the COWSOs were replaced by CBWSOs and these are expected to have the frontline responsibility for sustaining rural water supply and sanitation services on behalf of the beneficiaries (communities). The members of CBWSOs are drawn from the users but their qualifications and experiences have been better specified under the Act No.5. The minimum qualifications of the technical staff employed by CBWSOs has also been explicitly specified to ensure they have the requisite capability and experience. Their roles as well as the assumed responsibility of CBWSOs are also explicitly highlighted in the Act No.5 as well as the roles of RUWASA at different levels.

1.2.3 Coverage and Access to Water Supply Services

While the responsibility for provision of sanitation services in rural areas is principally under the Ministry of Health, Community Development, Gender, Elderly and Children (MoHCDGEC); following enactment of the Water and Sanitation Act No. 5 of 2019, RUWASA has also been given some responsibility to coordinate delivery of sanitation services in areas that are under its jurisdiction. In areas served by former National Project Water Utilities (WSSA), it is expected that the MoHCDGEC will liaise closely with both the latter and RUWASA to deliver sanitation services. It is estimated that by 2019, on average 21.2% of Tanzanians had access to safely managed sanitation (MoW AGM, 2019) against a National target of 25%.

1.2.4 Policy Environment for Water and Sanitation Services in Tanzania

The management of water resources in Tanzania is guided by the National water policy of 2002 (URT, 2002) that has been in use over the last 18 years and was further articulated by the National Water Sector Development Strategy of 2006 - 2015 (URT, 2008) and the WSDP of 2006-2025. There are currently efforts to update the national water policy by the Ministry responsible for Water. The most important national legislation guiding water resources management include the Water Resources Management Act No.11 (URT, 2009) and all subsequent amendments as well as the various regulations prepared by the Ministry responsible for Water.The Water Supply and Sanitation Act No.5 (URT, 2019) and the associated regulations prepared by the Ministry responsible for Water guide the development of water supply and sanitation services in Tanzania. The users of this manual are referred to the URT website for further information.

As regards sanitation, the Public Health Act of 2009 and The Health Policy of 2007 provide the relevant legal guidance. Other relevant guiding documents include The National Guidelines for Water, Sanitation and Hygiene for Tanzania Schools (MoEST, 2016), National Guidelines for Water, Sanitation and Hygiene in Health Care Facilities (MoHCDGEC, Oct. 2017), Guidelines for the Preparation of Water Safety Plans (MoW, Oct. 2015), National Guidelines on Drinking Water Quality Monitoring & Reporting (MoW, Jan. 2018) and Guidelines for the Application of Small-Scale, Decentralized Wastewater Treatment Systems; A Code of Practice for Decision Makers (Mow, Dec. 2018). Another Swahili document is titled “Mwongozo wa Ujenzi wa Vyoo Bora na Usafi wa Mazingira” (Guidelines for Construction of Toilets and Sanitation), (MoHCDGEC, 2014).

1.2.5 Major Stakeholders in Water Supply and Sanitation Projects

Effective and efficient implementation of water supply and sanitation projects will be achieved through the contribution of a number of stakeholders. The stakeholders of significant importance are described below.

(a) Regulatory Authorities
In order to ensure the smooth implementations of water supply and sanitation projects, various regulatory authorities have been established from time to time. The latter, monitor professional conduct of the different parties involved in water and sanitation projects. These include:
(i) Public Procurement Regulatory Authority (PPRA),
(ii) Tanzania Bureau of Standards (TBS),
(iii) Engineers Registration Board (ERB),
(iv) Contractors’ Registration Board (CRB),
(v) Energy and Water Utilities Regulating Authority (EWURA),
(vi) The National Environmental Management Council (NEMC).

(b) Contractors and Consultants
Contractors are the firms that perform the actual construction of the water projects according to the agreed terms in the contracts. Consultants/Project Managers are firms that design water supply and sanitation projects and supervise the construction works depending on the terms and conditions specified in their respective contracts. Moreover, the consultant, on behalf of the client, approves completed structures with regards to the specifications given and the standards required as elaborated in chapter twelve of Volume I of the DCOM manual

(c) National Water Supply and Sanitation NGOs and networks
The following is a sample list of Non-Governmental Organizations (NGOs) that deal with a water supply and sanitation services in Tanzania and hence have a contributing role to the Ministry of Water (MoW):
(i) Association of Tanzania Water Suppliers (ATAWAS),
(ii) Tanzania Water Supply and Sanitation Network (TAWASANET),
(iii) Tanzania Global Water Partnership (GWPTZ).

1.2.6 Water Supply and Sanitation Public-Private Partnership in Tanzania

The national water policy (NAWAPO) of 2002 (URT) envisaged devolution elements to be introduced as well as public and civil service reforms. It had assumed that the Central Government would provide technical and financial support, coordination and regulation of water supply development while the private sector was expected to support the communities in planning, design, construction and supply of materials, equipment, spare parts and to support operations in some cases. The Development Partners (DPs), NGOs and CBOs were expected to provide funding and technical assistance to supplement the Government’s efforts through basket funding.

In support of the Government the Public-Private Partnership (PPP) policy of 2009 as also supported by EWURA which prepared the PPP guidelines for water supply and sanitation (EWURA, 2017) and the relevant legislation that was stipulated in NAWAPO 2002, the MoW has created the necessary environment for supporting the private sector such that, a sizeable proportion of the works, services and goods are procured from private sector Service Providers (SPs) hence assisting the Government in fulfilling its roles.

Essentially, one of the successes of NAWAPO 2002 has been the inclusion of the private sector in water supply and sanitation projects implementation. Notwithstanding the good experiences, the MoW (2018) indicated that even though the Water Sector Development Programme (WSDP) Project Implementation Manual gave a lot of opportunities to the private sector that procured most of the works, field experience has shown that the capacity of the private sector in Tanzania is limited in terms of having only a few staff and thereby failing to supervise the works properly.

On the other hand, the Ministry of Water organized a forum on enhancing public private partnership in the water sector. This was held in Dar es Salaam from 19 to 20 July 2018. In this forum, discussions were held with the private sector stakeholders where experiences, challenges and recommendations were obtained with regard to implementation of rural water supply projects in Tanzania. The forum was a follow up of the Five-Year Development Plan (FYDP) 2016/17-2020/21. The fourth priority area of the FYDP is strengthening project implementation effectiveness, which earmarked water supply and sanitation one of the key interventions for achievement. In the forum, the following key issues were captured:
(a) Contract management issues such as delays in decision making by the client,
(b) Payment problems,
(c) Procurement problems,
(d) Policy issues on Tax exemption for imports,
(e) Political interference in the execution of works,
(f) Knowledge gap on current technology available for groundwater exploration based on quality and quantity of water,
(g) Shortage of contractors with capacity to execute water supply projects,
(h) Database issues especially on water resources information, which often end up with over- or under- designing water supply facilities.
(i) Design specifications based on the use of obsolete technologies was identified as a critical problem.

Privatization of some or all functions of Operation and Maintenance can be considered to achieve:
(i) efficiency
(ii) economy
(iii) professionalism and
(iv) financial viability of the system.
In order to achieve the above stated objectives, the private entrepreneur needs to possess:
(i) adequately trained, qualified staff for operation and supervision of the services
(ii) equipment, material, testing and repairing facilities
(iii) experience in operating similar systems
(iv) financial soundness
(v) capacity to meet the emergency situations.

In order to assist service providers/operators in ensuring financial viability of their projects through Public-Private Partnerships, the following were recommended:
(a) The MoW, through the established in-house Design Unit should provide an option for on-demand engagement of the private sector at the project level, in cases where in-house capacity or technology is limited;
(b) Enhancement of awareness on other operational modes in PPP as per water policy;
(c) Where applicable, private operators should be engaged in operation and maintenance of water supply and sanitation services after due diligence; The same applies to contracting personnel with specialized skills for the repair and maintenance of specialized equipment or instrumentation as specialized services for maintenance of such equipment instead of employing additional staff. Such a practice may ensure proper functioning of the equipment with least cost;
Private operators should be supervised closely to avoid challenges in operation and maintenance of water supply and sanitation projects (i.e. water supply connections, facilities and finances).

1.3 Rationale For The Preparation Of The Fourth Edition Dcom Manual

The need to review and update the 2009 Design Manual was emphasised during the Private-Public Partnership (PPP) stakeholders’ meeting hosted by the MoW in 2018. During that meeting, the issue of providing designs/specifications that use old technologies in procurement was indicated as a concern as well as stressing the need to adopt the latest and appropriate technology. Among the Recommendations of the Special Committee on Audit of WSDP I & II projects in rural areas in Tanzania (URT, Nov. 2018), the need to review and update the design manual and to ensure that all consultants use it was emphasized. The four volumes of the DCOM manual have been prepared in order to facilitate effective complimentary planning, design, construction supervision as well as operation and maintenance of water supply and sanitation projects for urban, peri-urban and rural areas of Tanzania.

The manuals will also assist the staff of the Ministry responsible for water and sanitation projects to effectively undertake their supervisory and coordination roles and the consultants to undertake designs using the guidelines recommended in the MoW manual. For Urban and National WSSA or RUWASA staff who may be involved in design, construction supervision of projects using the Force Account mode of implementation, the four manuals will prove to be useful in facilitating step by step supervision. On the other hand, for staff who will be implementing water supply and sanitation projects, the manuals will provide guidance on how they should involve all the principal stakeholders including the Community Based Water Supply Organizations (CBWSO) as foreseen in both the NAWAPO (URT,2002) as well as the NWSDS (URT, 2008).

The manuals have been formatted in order to be more user friendly by allowing navigation within and across the manuals as well as having the capability to navigate into or from website links with ease using subject indices that enable a user to search for the needed information almost instantly. It is hoped that, the manuals will contribute towards improvement of the contract management capacity of the staff involved in project management and will eliminate the recurring problem of consultants designing water supply and sanitation management projects that are below minimum quality standards.

1.4 About The Fourth Edition Of The Dcom Manual

The 4th edition of the DCOM Manual was prepared in 2020, following the review and updating of the Third Edition of the Water Supply and Wastewater Disposal Design Manual of 2009. The former manual was prepared in three separate volumes. These volumes included eight chapters on water supply, three chapters on wastewater disposal and one chapter on water pipelines standards and specifications. It should be remembered that the 2nd Edition of the Design Manual that was titled Design Manual for Water Supply and Wastewater Disposal was prepared in July 1997 in two volumes with eight chapters and three chapters, respectively. The 1st Edition of the Design Manual was prepared in 1985/86, a few years after the conclusion of the International Water and Sanitation Decade that ended in 1981. Thus, the current edition of the DCOM is adequately informed by previous edition reviews which incorporate topical and existing challenges and issues.

A Special Committee of twelve members from The Ministry of Water, RUWASA, University of Dar es Salaam (UDSM), The Nelson Mandela African Institution of Science and Technology (NMAIST) and Private Sector undertook the preparation of the four volumes of this manual. The process of preparing the design manuals entailed a number of participatory consultations with key stakeholders from the water and sanitation sector as well as from Ministries of Education, Science & Technology, Ministry of Health, Community Development, Gender, Elderly and Children (MoHCDGEC), President’s Office Regional Administration and Local Government (PORALG) as well as Consultants, Contractors, Materials suppliers and Development Partners. It also involved undertaking an extensive search of literature from libraries, conference proceedings, journal publications, websites of various entities and design manuals from various global, East African and SADC countries

1.5 Organisation Of The 4th Edition Of The Dcom Manual

The 4th Edition of the DCOM Manual has been prepared in four separate volumes that are divided as follows:

  • Volume I which presents Design of Water Supply Projects organized into thirteen chapters;
  • Volume II that dwells on Design of Sanitation Projects and is divided into six chapters;
  • Volume III titled Construction Supervision for Water Supply and Sanitation Projects has been structured into five chapters;and
  • Volume IV titled Operation and Maintenance for Water Supply and Sanitation Projects is organized into nineteen chapters.

This Volume IV is organized into five parts as indicated below, and can be used as separate packages for training of different groups of users from the water sector:
Part A: Essentials of Operation & Maintenance,
Part B: O&M of the Water Supply Sources and Network,
Part C: O&M of Water Treatment, Water & Wastewater Quality Compliance,
Part D: O&M of Sanitation Projects,
Part E: Water Audit, Revenue and Community Participation Management.

1.6 Purpose Of This Volume

This volume has been prepared with the main aim of providing engineers and designers with step by step design approaches for water supply projects. Observations gathered during the audit of water projects by special audit committee revealed that one of the reasons for poor performance of water projects is an outdated design manual. This very first volume of DCOM has been organized in such a manner that it starts with planning for water projects. The water projects planning chapter which comes after the introductory chapter underlines and underscores the significant and major part of the water projects. Also, the volume covers detailed account of assessment of safe yield of water sources. Water intakes, treatment and pipelines hydraulic analysis have been well covered in this volume. Chapter four provides description designs and specification. The role of stakeholders on water projects has been stipulated in the last chapter.

The preparation of this volume aimed to provide an opportunity to guide well engineers who have been given the responsibility for the design of either a complete water supply scheme or any component of the same as currently presented under 16 different topics. Volume I of the DCOM Manual has also provided the opportunity to link or hyperlink to many other websites and also to use the index provided at the end of the volume for ease of instant search


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