Chapter One: Introduction
The preparation of this DCOM manual has been preceded by an overview of four important global considerations of Water Supply and Sanitation prior to reviewing the water and sanitation sector in Tanzania. It is followed by explanation of the rationale for 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 1.1 Global Considerations on Water Supply and Sanitation
- 2 1.2 Development Agenda and Water and Sanitation Sector in Tanzania
- 2.1 1.2.1 National Water Policy
- 2.2 1.2.2 Legal and Institutional Framework for Water Supply and Sanitation Services
- 2.3 1.2.3 Coverage and Access to Water Supply Services
- 2.4 1.2.4 Policy Environment for Water and Sanitation Services in Tanzania
- 2.5 1.2.5 Major Stakeholders in Water Supply and Sanitation Projects
- 3 1.3 Rationale
- 4 1.4 About the Fourth Edition of the DCOM Manual
- 5 1.5 Organisation of the 4th edition of the DCOM Manual
- 6 1.6 Purpose of this Volume
- 7 1.7 References
1 1.1 Global Considerations on Water Supply and Sanitation
1.1 1.1.1 Sustainable Development Goals (SDGs)
In 2015, world leaders came together at the United Nations in New York and adopted the 2030 Agenda for Sustainable Development. Governments responded to the common development challenges they faced and the changing world around them by uniting behind a truly forward-looking, yet urgent plan to end poverty and create shared prosperity in a healthy and peaceful planet. The Agenda 2030 central principle is leaving no one behind in achieving the 17 Sustainable Development Goals (SDGs) through 169 targets. The 2030 Agenda for Sustainable Development adopted at the UN Summit includes the 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. It should also be noted that, water and sanitation are at the heart of the Paris Agreement on climate change 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 now to transform the way it manages its 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 to achieve the SDG 6, where population growth and rapid urbanisation have intensified demand for water and sanitation services beyond all past thresholds. .
1.2 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 and intense extreme weather events have resulted in a higher incidence of floods and droughts around the planet. The ensuing adverse impacts of climate change on water and sanitation services constitute a clear and present danger for development and health. Ensuring optimal resilience of water and sanitation services in a globally changing climate context will be crucial for maintaining the momentum of making progress in health and development. Climate variability is already a threat to the sustainability of water supplies and sanitation infrastructure.
Floods are “normal” occurrences that continue to cause shocks for the affected population and to challenge water and sanitation managers. In many places they 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 neighbourhoods 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 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 Intergovernmental Panel on Climate Change (IPCC). Accordingly, designers should therefore use the latest information, data and model predictions available and include a statement on what measures, if any, have been allowed for in order to cope up with the climate change within the time frame of their project design (i.e. design life).
1.3 1.1.3 International Water Association
The International Water Association (IWA) is the network of water professionals striving for a world in which water is wisely, sustainably and equitably managed. The IWA is an international reference for the water and sanitation industry. The IWA membership communities contribute and develop the IWA Agenda.
1.4 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 types of water sources are managed using international law.
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 the non-navigational uses of international watercourses (https://www.siwi.org/icwc-course-international-water-law/).
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 is the 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 doctrines 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).The soft law of the Sustainable Development Goals (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 decision making.
Management of water resources that entails extraction of shared international water resources in form of rivers, lakes, seas and oceans for sources are guided by the 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 that can be found in the respective websites. 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.
2 1.2 Development Agenda and Water and Sanitation Sector in Tanzania
The Tanzania Development Agenda include the Tanzania Development Vision (TDV) 2025 (https://www.mof.go.tz/mofdocs/overarch/vision2025.htm). The realization of TVD 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 (https://mof.go.tz/mofdocs/msemaji/Five%202016_17_2020_21.pdf). The Government adopted the TDV in the mid-1986s for socio-economic reforms and continue 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 is shaping the future in which water and sanitation services will be delivered to enhance the health of normal citizens who are very important 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, namely industrialization, human development, and implementation effectiveness, and is aligned well to its SDGs. Importantly, industrialization will place a huge demand on utility supplies e.g. energy and water, so subscribing on addressing the SDG Goals 6: on water and sanitation.
Chapter 4 of FYDP II, sub-chapter 4.3.4 on Water Supply and Sanitation Services sets key targets as follows; 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: 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 key targets of water supply and sanitation is the effective application of 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 in terms of water coverage for rural areas and urban areas are 85% and 95% by 2025 respectively which are also articulated by 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 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 on-going 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. As regards 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, Tanzania is lagging behind by far.
2.1 1.2.1 National Water Policy
The National Water Policy (NAWAPO) of 2002 guides 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 explained to be put in place. The policy aimed at ensuring that 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 by assurance of improved water supply and sanitation services to the water users and to identify and preserve the water sources.
2.2 1.2.2 Legal and Institutional Framework for Water Supply and Sanitation Services
Basically, the water and sanitation sector is governed through 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 coordinate water supply and sanitation delivery service: 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 will be responsible for planning and managing, and supervising the rural water supply and sanitation projects, including financial and procurement management, and 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 thoroughly in most of the implemented projects through establishment of COWSOs in every completed projects that were given all the mandate of making sure the projects are sustainable.
However, according to the Water Supply and Sanitation Act No. 5 of 2019, the COWSOs were replaced by CBWSO and these are expected to have the frontline responsibility for sustaining rural water supply and sanitation services on behalf of the beneficiaries (community). The members of CBWSO are drawn from the users but their qualifications and experiences have been better specified under the Act No.5. The minimum qualification of the technical staff to be 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 CBWSO are also explicitly highlighted in the Act No.5 as well as the roles of RUWASA at different levels.
2.3 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, RUWASA also has some responsibility to coordinate delivery of sanitation management 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%.
2.4 1.2.4 Policy Environment for Water and Sanitation Services in Tanzania
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 that was further articulated by the National Water Sector Development Strategy of 2006 - 2015 (URT, 2008). There are current 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 (www.maji.go.tz) 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 document in Swahili is titled “Mwongozo wa Ujenzi wa Vyoo Bora na wa Usafi wa Mazingira” (Guidelines for Construction of Toilets and Sanitation), (MoHCDGEC, Oct. 2014).
2.5 1.2.5 Major Stakeholders in Water Supply and Sanitation Projects
The effective and efficient implementation of water supply and sanitation projects will be achieved through contribution of a number of stakeholders. Those stakeholders of significant importance are described below;
(i) Regulatory Authorities In order to ensure smooth implementations of water supply and sanitation projects various regulatory authorities have been established from time to time. The latter, monitor professional conducts of the different parties involved in water and sanitation projects. These include:
- Public Procurement Regulatory Authority (PPRA) (https://www.ppra.go.tz/),
- Tanzania Bureau of Standards (TBS) (http://www.tbs.go.tz/),
- Engineers Registration Board (ERB) (https://www.erb.go.tz/),
- Contractors Registration Board (CRB) (http://www.crb.go.tz/),
- Energy and Water Utilities Regulating Authority (EWURA) (https://www.ewura.go.tz/).
- The National Environmental Management Council (NEMC) (http:www.nemc.go.tz)
(ii) 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 four of this volume of the DCOM manual
(iii) National Water Supply and Sanitation NGOs and networks
The following is a sample list of Non-Governmental Organizations(NGOs) that deals with water supply and sanitation services in Tanzania and hence have a contributing role to the Ministry of Water (MoW):
• Association of Tanzania Water Suppliers (ATAWAS)(http://atawas.or.tz/), • Tanzania Water Supply and Sanitation Network (TAWASANET)(http://www.tawasanet.or.tz/), • Tanzania Global Water Partnership (GWPTZ) (https://www.gwptz.org/about/).
3 1.3 Rationale
The need to review and update the Design Manual was emphasised during the Private Public Partnership (PPP) stakeholder’s meeting hosted by the MoW in 2018. During that meeting, the issue of providing designs/specifications that use old technologies in procurement was mentioned as well as stressing the need to adopt the latest appropriate technology. Among the recommendations of the Special Committee on Audit of WSDPI & II projects in rural areas in Tanzania (URT, Nov. 2018), the need to review and update the design manual and to ensure 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 to undertake their supervisory and coordination roles well 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 the water supply and sanitation projects, the manuals will provide guidance on how they have to involve all the principal stakeholders including the Community Based Water Supply Organisations (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 indices that facilitate one 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 it will eliminate the recurring problem of consultants designing water supply and sanitation projects that are below minimum standards.
4 1.4 About the Fourth Edition of the DCOM Manual
The 4th edition of the DCOM Manual has been prepared in the year 2020, following review and updating of the Third Edition of the Water Supply and Wastewater Disposal Design Manual of 2009. The former 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 however be remembered that the 2nd Edition of the Design Manual that was titled Design Manual for Water Supply and Waste and Waste Water 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 the year 1985/86, a few years after conclusion of the International Water and Sanitation Decade that ended in 1981. Thus, the current edition of DCOM is adequately informed by previous edition reviews which incorporate the 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 preparation of the four volumes. The process of preparation of 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.
5 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 that is organized into six chapters. Volume II that dwells into Design of Sanitation Projects is divided into five chapters. Volume III which is titled Construction and Supervision for Water Supply and Sanitation Projects has been structured into ten chapters while Volume IV titled Operation and Maintenance for Water Supply and Sanitation Projects is organized into seven chapters.
6 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 of 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. the 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 introduction chapter underlines and underscores the significant 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 narrated in last chapter. The preparation of this volume was to provide an opportunity to guide well engineers who have been given the responsibility for design of either a complete water supply scheme or any component of the same as currently presented under 16 different topics. The 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 to make instant search.
7 1.7 References
UNFCCC (2015). Paris Agreement. United Nations Framework Convention on Climate Change (UNFCCC).
URT (2000). The Tanzania Development Vision 2025. Ministry of Finance and Planning. https://www.mof.go.tz/mofdocs/overarch/vision2025.htm.
URT (2002). The National Water Policy (NAWAPO). United Republic of Tanzania (URT).
URT (2008). The National Water Sector Development Strategy (NWSDS). United Republic of Tanzania.
URT (2014). Guidelines for Construction of Toilets and Sanitation. Ministry of Health, Community Development, Gender, Elderly and Children (MoHCDGEC).
URT (2016). The National Guidelines for Water, Sanitation and Hygiene for Tanzania Schools. Ministry of Education, Science and Technology (MoEST).
URT (2016). The Second Five Year Development Plan (FYDP II), 2016/17 – 2020/21. Ministry of Finance and Planning. https://mof.go.tz/mofdocs/msemaji/Five%202016_17_2020_21.pdf.
URT (2017). National Guidelines for Water, Sanitation and Hygiene in Health Care Facilities. Ministry of Health, Community Development, Gender, Elderly and Children (MoHCDGEC). NSGRP II & III