Tanzania Ministry of Water Design Manual 4th Edition

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VOLUME I: DESIGN OF WATER SUPPLY PROJECTS

Chapter 1: Introduction

The preparation of this DCOM manual has been preceded by an overview of four important global consideration of Water Supply and Sanitation prior to reviewing the water and sanitation sector in Tanzania. It is 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.

Global Considerations on Water Supply and Sanitation
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 [1]. 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 as indicated in SDG6.

Therefore, the designers and engineers have the responsibility to support the Government to achieve the SDG 6, where population growth and rapid urbanization have intensified demand for water and sanitation services beyond all past thresholds.

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 and therefore it must 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). Further information on the impacts of climate change and resilience is given in appendix A.


The existing design manual for water supply [2] and wastewater disposal (3rdedition) was formally adopted by the Ministry that was responsible for Water in 2009 and it consists of three parts namely; volume I on Water supply, volume II on Wastewater disposal and volume III on Water pipelines standards and specifications. Since it is now nearly ten years since the third edition of the design manual was adopted and in the meantime, many scientific and technological changes have taken place including the conclusion of MDGs and adoption of the SDGs in 2015 as well as learning some useful lessons out of implementation of the WSDP I and WSDP II (which is still ongoing); it is felt it is high time to revise the design manual [3]

manual.

Genesis/Background

The existing design manual for water supply and wastewater disposal (3rdedition) was formally adopted by the Ministry that was responsible for Water in 2009 and it consists of three parts namely; volume I on Water supply, volume II on Wastewater disposal and volume III on Water pipelines standards and specifications. Since it is now nearly ten years since the third edition of the design manual was adopted and in the meantime, many scientific and technological changes have taken place including the conclusion of MDGs and adoption of the SDGs in 2015 as well as learning some useful lessons out of implementation of the WSDP I and WSDP II (which is still ongoing); it is felt it is high time to revise the design manual.

Underground Tank

Rationale

The existing design manual for water supply and wastewater disposal (3rdedition) was formally adopted by the Ministry that was responsible for Water in 2009 and it consists of three parts namely; volume I on Water supply, volume II on Wastewater disposal and volume III on Water pipelines standards and specifications. Since it is now nearly ten years since the third edition of the design manual was adopted and in the meantime, many scientific and technological changes have taken place including the conclusion of MDGs and adoption of the SDGs in 2015 as well as learning some useful lessons out of implementation of the WSDP I and WSDP II (which is still ongoing); it is felt it is high time to revise the design manual.

Organisation/description of the manual

The existing design manual for water supply and wastewater disposal (3rdedition) was formally adopted by the Ministry that was responsible for Water in 2009 and it consists of three parts namely; volume I on Water supply, volume II on Wastewater disposal and volume III on Water pipelines standards and specifications. Since it is now nearly ten years since the third edition of the design manual was adopted and in the meantime, many scientific and technological changes have taken place including the conclusion of MDGs and adoption of the SDGs in 2015 as well as learning some useful lessons out of implementation of the WSDP I and WSDP II (which is still ongoing); it is felt it is high time to revise the design manual.

ESIA and EIA Compliance

The existing design manual for water supply and wastewater disposal (3rdedition) was formally adopted by the Ministry that was responsible for Water in 2009 and it consists of three parts namely; volume I on Water supply, volume II on Wastewater disposal and volume III on Water pipelines standards and specifications. Since it is now nearly ten years since the third edition of the design manual was adopted and in the meantime, many scientific and technological changes have taken place including the conclusion of MDGs and adoption of the SDGs in 2015 as well as learning some useful lessons out of implementation of the WSDP I and WSDP II (which is still ongoing); it is felt it is high time to revise the design manual.

Water supply

The existing design manual for water supply and wastewater disposal (3rdedition) was formally adopted by the Ministry that was responsible for Water in 2009 and it consists of three parts namely; volume I on Water supply, volume II on Wastewater disposal and volume III on Water pipelines standards and specifications. Since it is now nearly ten years since the third edition of the design manual was adopted and in the meantime, many scientific and technological changes have taken place including the conclusion of MDGs and adoption of the SDGs in 2015 as well as learning some useful lessons out of implementation of the WSDP I and WSDP II (which is still ongoing); it is felt it is high time to revise the design manual.

Design of Infrastructure: intakes, rising main pipelines, break pressure tanks, washout & air release values, various different valves, storage tanks, distribution pipelines, water points & soak pits

Design of water supply networks
Types of networks (e.g. grid, loops, etc.)
Design methodologies
Transmission main
Distribution network
Storage tanks
Units costs
Gravity schemes
Pumping systems

Appendix: Drawings

List of drawings organized per category:

Appendix I: Water Treatment

This section presents various drawings related to Water Treatment

Sand Filter
Layout of Horizontal-Flow Roughing Filter
Vertical-Flow Roughing

Appendix 2: House Water Connections Models

This section presents various drawings related to House Water Connections Models

House Water Connection Model
Single Tap DP
Double Tap DP

Appendix 3: Structural Drawings

This section presents various structural drawings

45M3 Tank on 6M Riser Reinforcement
45M3 Tank on 6M Riser Elevation
45M3 Tank on 6M Riser Blockwork

References

  1. Helping governments and stakeholders make the SDGs a reality. Retrieved 1 March 2020.
  2. 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.
  3. URT (2017). National Guidelines for Water, Sanitation and Hygiene in Health Care Facilities. Ministry of Health, Community Development, Gender, Elderly and Children (MoHCDGEC).