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Document 524 PRELIMINARY DESIGN REPORT CHAPTER: University of Minnesota COUNTRY: Uganda COMMUNITY: Bugonzi PROJECT: Household Rainwater Harvesting Systems

PREPARED BY

Kristina Coster, Stephanie Vogeli, Jane Dupay, John Bartoletta, Roland Welter, Kristin Carlson, Reed Saunders, Jordan Gustafson, Emily Mattison, Joseph Casanova, Collin Smith, Laina Breidenbach

December 16th, 2012

ENGINEERS WITHOUT BORDERS-USA www.ewb-usa.org

524 - Preliminary Design Report Revised 12/14/2012 EWB-UMN Bugonzi, Uganda Household Rainwater Harvesting Systems

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Table of Contents page

Administrative Information 1.0 Contact Information 3 2.0 Travel History 3 3.0 Monitoring 4 4.0 Budget 4 5.0 Project Discipline 8 6.0 Project Location 8 7.0 Project Impact 8 8.0 Professional Mentor/Technical Lead Resume 9 Technical Information

1.0 Executive Summary 11 2.0 Introduction 14 3.0 Program Background 14 4.0 Facilities Design 16 5.0 Project Ownership 21 6.0 Constructability 22 8.0 Sustainability 24 9.0 Monitoring 25 10.0 Community Agreement/Contract 26 11.0 Professional Mentor/Technical Lead Assessment 28 Appendices

A Calculations 30 B Drawings 40 C Tank Size Decision 55


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Preliminary Design Report Part 1 – Administrative Information

1.0 Contact Information Project Title Name Email Phone Chapter Name

or Organization

Name

Project Leads Stephanie Vogeli

Vogel284@ umn.edu

(206)930-1825 UMN

President Samantha Ehrenberg

Ehren021@ umn.edu

(320)241-9787 UMN

Mentor #1 Jeff Weiss Jalalabadjeff@ hotmail.com

(612)817-7183 Medtronic

Mentor #2 Walter Eshenaur

weshenaur@srf consulting.com

(651)334-4854 SRF Consulting Group, Inc.

Faculty Advisor (if applicable)

Timothy LaPara Julian Marshal

lapar001@ umn.edu julian@umn. Edu

(651)387-2860 (651)625-2397

UMN UMN

Health and Safety Officer

TBD

Assistant Health and Safety Officer

TBD

Education Lead TBD

NGO/Community Contact

John Mary Lugemwa

jmlugemwa@ gmail.com

(320)363-3949 Uganda Rural Fund

2.0 Travel History

Dates of Travel Assessment or Implementation

Description of Trip

August 2007 Assessment Initial Site Visit

6/07/09 - 6/24/08 Phase I Implementation Rainwater harvesting system and improved sanitation for the HIA

6/01/09 - 6/30/09 Phase II Implementation Groundwater supply and distribution for the HIA

1/4/10 - 1/24/10 Phase III Assessment Assessment for improved stoves, economic development, POU water treatment


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6/1/10 - 6/21/10 Phase III Implementation Implemented 60 improved cookstoves in households, built 5 micro-irrigation systems

6/20/11 - 7/6/11 Phase IV Assessment Assessment of community water sources for future projects

5/01/2012- 6/1/2012 Phase IV Implementation Implementation of the rainwater harvesting system of the Bugonzi Primary School

3.0 Monitoring - Identify Projects to be Monitored on this Trip

4.0 Budget

4.1 Project Budget Project ID: _______________3665____________________ Type of Trip: _____________I____________________

Trip type: A= Assessment; I= Implementation; M= Monitoring & Evaluation

Trip Expense Category Estimated Expenses

Direct Costs

Travel

Airfare $16,200.00

Gas $0.00

Rental Vehicle $250.00

Project Type Project Discipline(s) Date of Completion (m/d/y)

Latrines at HIA Sanitation 2008

Groundwater System at HIA

Source Development, Water Storage

6/01//09-6/30/09

Microirrigation Irrigation Line 6/21/2010

Improved Cookstoves Air Quality 6/21/2010

Rainwater Harvesting System on the Bugonzi Primary School

Source Development 6/1/2012


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Taxis/Drivers $250.00

Misc. $250.00

Travel Sub-Total $17,000.00

Travel Logistics

Exit Fees/ Visas $450.00

Inoculations

Insurance $324.00

Licenses & Fees

Medical Exams

Passport Issuance

Misc.

Travel Logistics Sub-Total $774.00

Food & Lodging

Lodging $1,800.00

Food & Beverage (Non-alcoholic)

Misc.

Food & Lodging Sub-Total $1,800.00

Labor

In-Country logistical support

Local Skilled labor $500

Misc.

Labor Sub-Total $500

EWB-USA

Program QA/QC (1) See below $0

EWB-USA Sub-Total $0

Project Materials & Equipment (Major Category Summary) add rows if needed

Gutters TBD

Tanks TBD

Equipment TBD

Project Materials & Equipment Sub-Total $600.00*

Misc. (Major Category Summary)

Report Preparation

Advertising & Marketing

Postage & Delivery

Misc. Other


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Misc. Sub-Total $0

TOTAL $20,674.00*

(1) Program QA/QC Assessment = $1,500 Implementation = $3,675 Monitoring = $1,125

EWB-USA National office use:

Indirect Costs

EWB-USA Program Infrastructure (2) See Below $0

Sub-Total $0

TRIP GRAND TOTAL (Does not include Non-Budget Items)

$20,674.00*

(2) Program Infrastructure Assessment = $500 Implementation = $1,225 Monitoring = $375

Non-Budget Items: Additional Contributions to

Project Costs

Community

Labor

Materials

Logistics

Cash

Other

Community Sub-Total $0

EWB-USA Professional Service In-Kind

Professional Service Hours

Hours converted to $ (1 hour = $100) $0

Professional Service In-Kind Sub-Total $0

TRIP GRAND TOTAL (Includes Non-Budget Items) $20,674.00*


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Chapter Revenue

Funds Raised for Project by Source

Actual Raised to Date

Source and Amount (Expand as Needed)

Engineering Societies

Corporations

University

Rotary

Grants - Government

Grants - Foundation/Trusts

Grants - EWB-USA program

Other Nonprofits

Individuals $6000

Special Events

Misc.

EWB-USA Program QA/QC Subsidy (3) See below

EWB-USA Program Infrastructure Discount Amount

Total $6000.00

Remaining Funds Needed $14,674.00*

(3) Program QA/QC & Infrastructure Subsidy: Assessment = $1500 Implementation = $3,900 Monitoring = $1,000

*The cost for the materials is pending our assessment trip and the final decision on the tank

design. This cost will vary depending on the final tank design chosen so for now an estimate of

$600 has been used.


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4.2 Donors and Funding

Donor Name Type (company, foundation, private,

in-kind) Account Kept at EWB-USA?

Amount

Members of Travel Team Private No $6000.00

Total Amount Raised: $6000.00

5.0 Project Discipline(s): Check the specific project discipline(s) addressed in this report. Check all that apply.

Water Supply _X__ Source Development _X__ Water Storage ____ Water Distribution ____ Water Treatment ____ Water Pump Sanitation ____ Latrine ____ Gray Water System ____ Black Water System Structures ____ Bridge ____ Building

Civil Works ____ Roads ____ Drainage ____ Dams Energy ____ Fuel ____ Electricity Agriculture ____ Irrigation Pump ____ Irrigation Line ____ Water Storage ____ Soil Improvement ____ Fish Farm ____ Crop Processing Equipment Information Systems ____ Computer Service

6.0 Project Location Latitude: 31.389891081 ° E Longitude: 0.353551 ° S

7.0 Project Impact Number of persons directly affected: 2 or 3 households in first implementation. This

will increase as the system is adopted by members in the community. The households

will be chosen during the January assessment trip.

Number of persons indirectly affected: 350 (Community)


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8.0 Professional Mentor/Technical Lead Resume -

JEFFREY P. WEISS

1150 Woodcrest Avenue, Shoreview MN 55126

Phone: 612-817-7183; E-mail: [email protected]

Professional History

Medtronic, Inc: Minneapolis, MN; January 2006 to Present

Principal Manufacturing Engineer: CRDM Therapy Deliver Leads Automation Engineering

Group

● Research and develop new manufacturing technologies and processes for use in a

highly regulated industry.

● Responsible for the development and implementation of projects to include cost, project

management, coordination, and execution.

● Project coordinator and representative for the Operations group in new technology

program for cardiac leads.

Progressive Systems, Inc: Minneapolis, MN; July 2000 to 2006

Senior Design Engineer: Designed and built custom industrial equipment for the wood industry

that significantly increased productivity while reducing rework.

● Designed and updated a product assembly line for the company that led to higher

quality, more consistency, and 25% greater output.

● Improved existing designs and updated machines to incorporate quick changeover

principles. In one case this reduced a tool change operation from 25 minutes to 40

seconds.

● Responsible for project management, costs, and customer relations while functioning as

both a project leader and a team member.

Factory Systems Engineering, Inc.: Oakdale, MN; February 1993 to July 2000

Senior Mechanical Engineer: In-house and customer located mechanical engineering

assignments designing and building specialty factory automation equipment and retrofitting

existing lines for performance improvement.

● Project leadership and team member positions provided exposure to a variety of

industries including medical, electronics, packaging, and food.

● Requested by customers for additional projects because of a good work ethic and

adaptability.

United States Army Reserve: Service obligation ended in June 2004

Civil Affairs Team Leader: Responsible for the organization, activities, and operation of a Civil

Affairs Team in a remote area of Afghanistan.


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● Awarded a Bronze Star Medal for meritorious service in dealing with village leaders,

contractors, and the US government while managing local projects worth over 3 million

dollars.

● Received an award from the Joint Chiefs of Staff for exceptional supply operations while

working as the Battalion Logistics Officer.

● Mentored and developed junior officers and enlisted personnel.

Education

University of St. Thomas; St. Paul MN; 2006

Masters of Manufacturing Systems and Engineering degree.

Engineer In Training (EIT) Certified: 1993 (Fundamentals of Engineering Exam).

University of Minnesota; Minneapolis MN; 1992

Institute of Technology; Bachelor of Science, Mechanical Engineering.


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Preliminary Design Report Part 2 – Technical Information 1.0 EXECUTIVE SUMMARY

This report is made by the Bugonzi, Uganda- Water Supply (Individual

Rainwater Harvesting) project number 3665 of the EWB-USA UMN chapter. It contains

preliminary designs for individual household rainwater harvesting systems. One gutter

design and three tank designs are presented in this report. The tank designs will be

modified and adapted after a January 2013 assessment trip for this project. The final

design will be chosen based upon community feedback, material availability, and local

labor skill sets.

The goal of this project is to design a household rainwater collection system that

is low cost and relatively easy to implement. This will be introduced to the community

through an initial implementation and the goal is that it will then be adopted and

implemented by other community members, guided by those households and local

workers which are part of the initial implementation.

This community, Bugonzi, is off of the main road and as a result has limited

access to some supplies. The community members currently travel to collect their water

from ponds and ditches, and during the dry season travel up to 7 kilometers. Bugonzi

has a primary school, which our program has worked with in the past. It also has well

organized community leadership and a community organized water committee, with

which we will be coordinating during the assessment. Our chapter works with the

Uganda Rural Fund (URF) NGO, which operates Hope Integrated Academy. It is a

registered 501 (c) (3) non-profit and was founded in 2005. Its mission is “to empower

orphans, impoverished youth, and women in Uganda’s rural communities, through

educational and sustainable development opportunities.” Our Memorandum of

Understanding (MOU) has been drafted based on previous MOUs with the communities

and NGO. It will be presented to the community, individual households, and URF during

our January assessment trip for further finalization and discussion before all the relevant

parties sign it. The MOU will be edited to specify the particular commitments that the

households receiving the systems during the initial implementation agree to.

The initial assessment trip for this program was in August 2007. There have been

four previous projects through this program. The first project was implemented in 2008-

2009 and included a rainwater harvesting system and improved sanitation (latrine) for

Hope Integrated Academy (HIA). The second project was implemented in June 2009

and was a groundwater supply and water distribution system for HIA. The third project

was in June 2010 and was an implementation of 60 improved stoves throughout the

communities surrounding HIA and 5 micro-irrigation systems. The latest project , a

rainwater harvesting system on a primary school in the community of Bugonzi, was

implemented in May-June 2012. This school is in a neighboring community to HIA. This

project is the design and implementation of household rainwater harvesting systems for

families in the Bugonzi community. It is a direct product of the community’s and

community leader’s first priority for improvement: access to clean water within the


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community. An initial assessment for this project was completed in the summer of 2011,

an implementation in the summer of 2012, and a second phase of assessment will be

taking place in January 2013 in part to receive feedback on the designs presented in this

report.

The rainwater harvesting system will include gutters, a first flush system, and a

storage tank for the rainwater. The gutters are made of folded 1/8 inch galvanized steel

sheeting, and are hung from the household roofs using strips of 2 inch sheet metal

bands. The first flush system will be at the end of the gutters, and will make use of a

vertical PVC pipe branching downward from the horizontal pipe that runs into the tank.

Detailed descriptions of these components can be found below in the report. There are

three different tank designs presented in this report. One is made of cinder blocks, one is

of reinforced poured concrete, and one is Ferro-Cement, utilizing plaster layers and

chicken wire. Detailed descriptions of each tank design can be found later in this report.

The designs for all aspects of the system will be further edited after the assessment trip

to include community feedback, local material cost and availability, specific house

conditions, and the conditions of the areas surrounding the households.

The tank size of 2000 liters chosen for this project was based on rainfall data,

average roof area, and household water consumption feedback from the community.

More information about this can be found below in 4.1 Facilities Design and in Appendix

C. The galvanized sheet metal gutters will be hung from the roof using 2 inch wide sheet

metal bands and rebar and will have a 1% slope towards the tank. They will be folded

into a triangle-shape with an opening width of 7” and a depth of 5”. The first flush will be

made using a PVC pipe that is 2.3 feet long and 4” in diameter. Although the gutter and

first flush design remains the same for each proposed system, there are three different

tank options presented in this report:

● The block tank option will have dimensions of 76”x56”x64” on the exterior and

48”x40”x64” in the interior. It will be made out of 8”x8”x16” standard hollow blocks,

and will hold about 2,000 liters of usable water. It will be built on a concrete slab

base, reinforced with a 12 inch spaced rebar mesh. The walls will anchor to the

base with L-shaped rebar pieces, with the horizontal leg set into the concrete base

and the other placed in holes in the blocks. These L-shaped rebar pieces will be

placed in the middle of each of the two holes in each block. This means that they

will be spaced eight inches apart. The tank will sealed on the inside with a layer of

waterproofing mortar and paint-on sealant. The lid will be a metal sheet. The spigot

and drainage pipes will be cast in their own blocks in the bottommost course.

● The poured concrete tank option will be a cylinder 64 inches tall, 4.7 inches thick,

and have an inside radius of 27.5 inches. It will have a drainage pipe with a spigot

3 inches from the bottom of the tank. The tank will have vertical steel reinforcement

bars every 10 inches around the perimeter (19 total bars). The bent circular

horizontal steel reinforcement bars will be spaced every 10 inches with an extra

circle at the top of the tank (6 total bars). The base of the tank will have a mesh of

bars spaced every 10 inches, and a circular reinforcement around the perimeter

which will be connected to the vertical bars in the cylinder.


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● The Ferro-Cement tank option will have a cylindrical base with a radius of 29

inches and a height of 12 inches constructed out of layered brick and cement. The

height of the tank will be 55 inches, the largest diameter, towards the top of the

tank, will be 62 inches and the opening on the top will have a diameter of 24.25

inches. There will be four layers of plaster as the tank, with a total of 4 inches

thickness, with a chicken-wire wrap in the middle of the four layers. It will be built

around a rebar-burlap mold, which will be removed once construction is completed.

Further description of all aspects of these designs can be found below in 4.2 Description

of Design and Design Calculations .

Description of the drawings can be found below in section 4.2, and the project

drawings can be found in Appendix B. Appendix B.4 , starting on page 51, corresponds

to the gutter system and first flush systems. These drawings show the gutter design,

attachment, connection to first flush, and first flush system. Appendix B.1 on pages 42-

43 corresponds to the Ferro-Cement tank option, Appendix B.3 on pages 48-50

correspond to the block tank option, and Appendix B.2 on pages44-47 corresponds to

the poured concrete tank option. These drawings show the tank designs and bases,

including the overflows and outlets.

The construction of these tanks will be mostly taken on by local masons and the

families who are receiving the tank. The EWB team will assist, especially during the

initial implementation. The masons will be paid the standard wage, the family members

will be donating their time, and any community member who is interested in learning

about the tanks may come to help and learn. The EWB team will play a large role in the

initial implementation in teaching the techniques, explaining the designs,

troubleshooting, and working with the locals so that they could build systems themselves

in the future, as well as helping with the actual construction. The team will also have an

education plan in place, so community members can learn how to make and maintain

the tanks on their own. The construction process for the individual components of the

system is described in greater detail in the following parts of this document. A finalized

design for the system will be completed in time for an early summer 2013

implementation and education trip. After this, we will monitor through our NGO to see

how the community accepts the design and see what steps community members are

taking to make similar systems. If need be, we may return on another trip for education

or continued implementation on a few more homes as we encourage the community

members to use the design and skills we have given them to make their own systems or

hire locals to construct them.

This program is sustainable because it makes use of only resources that can be

acquired locally. During the January assessment trip, local costs will also be assessed to

ensure that the tanks will be able to be made with affordable, effective materials. Using

only local, cost effective materials means that future tanks can be built by the community

members, and that if a repair needs to be made, it can be done so using materials that

are locally available. The price of the system will be closely followed throughout the

design and construction processes to ensure the design is affordable for as many

community members as possible. The only common operation concern is the emptying


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of the first flush systems, which the homeowners will be taught. The long term

maintenance repairs may include replacing a portion of the gutter or first flush, or

patching of the tank or replacement of the tank outlet piping or spigot. Replacement or

repair components of the system may include 4”x10’ PVC Piping, (estimated 16,300

UGX per unit), 12”x18” Galvanized Steel Sheets (estimated 11,200 UGX per unit), Block

(estimated 157 UGX per unit), Concrete plaster (estimated 24,850 UGX per unit), and

rubber hose (estimated cost 5,000 UGX per unit) and can all be obtained nearby.

Further cost data will be collected during the January assessment trip to make sure that

we are doing what we can to make the system affordable. Because the household

members and community workers will be involved in the building of the tanks, they will

know how to do the needed repairs, and repairs will be addressed during the education

portion of our implementation trip.

2.0 INTRODUCTION

This document presents the preliminary designs for household-scale rainwater

harvesting systems, designed as part of this program’s work with Uganda Rural Fund

(URF) in Uganda and as part of our work with the community of Bugonzi. Community

members and leaders in Bugonzi identified water access as one of their chief priorities,

and during previous assessment and implementation trips in the area made it clear that

they support the idea of individual household collection systems. The design outlined in

this document consists of a system including gutters, a first flush, and a water storage

tank. The gutter and first flush design are presented below, along with three possible

options for the tank design. The three tank design options will be presented to and

discussed with the community during our upcoming assessment trip. The feedback

received from the community, along with other information gathered during the

assessment trip, will be used as we finalize and modify the tank design for

implementation in Bugonzi.

3.0 PROGRAM BACKGROUND During the past five years, the University of Minnesota chapter has been working

closely with Uganda Rural Fund (URF) to address issues of water supply and sanitation

in the Lwengo district of southwest Uganda.

The first phase (June 2008) was a Rainwater Harvesting System at a secondary

school (Hope Integrated Academy) that is run by URF. The rainwater harvesting system

provides the school with storage of 96,000 liters. It is currently used not only by the

students, but also their families and those living in close proximity to the school. URF is

responsible for the maintenance of the system and over the last four years has

demonstrated that they are capable of ensuring the long term success of the project. A

second project implemented in the first phase was a pair of dry composting toilets. This


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project has not been as successful because the students and staff prefer the traditional

pit latrines.

The second phase (June 2009) was the implementation of a groundwater

distribution system that provided URF the capacity to house 200 boarding students on

site. The system consisted of a submersible pump, solar panels, small storage tank and

several taps.

Phase Three consisted of two pilot projects. The first was the distribution of

improved cook stoves and extensive indoor air quality monitoring to validate the stoves.

The EWB team trained a 'Clean Air Team' made up of students at the secondary school

to educate their communities about air pollution and lung health. The other project was a

micro-irrigation pilot scheme. A women's group bought 'kits' and worked with the EWB

team to build micro-irrigation systems in group gardens.

In July 2011, an assessment team met with community leaders, government

officials, and community members to discuss possible future projects in the area. Some

of the projects that were requested included building clinics or staff houses, roads, water

distributions systems, and boreholes. Following this assessment trip, the Uganda

program split into two different projects. One worked on the design of a rainwater

harvesting system for the primary school in Bugonzi, one of the assessed communities.

That project was implemented in the summer of 2012.

This project is working on designing a household rainwater harvesting systems

for households in Bugonzi. This project builds on our chapter's existing expertise in

rainwater harvesting systems, developed through implementing and maintaining

systems in both Uganda and Guatemala. The project will be implemented in the

community of Bugonzi, with whom we have been in contact for at least four years,

building on rapport established during our June 2010 air quality and micro-irrigation

implementation and the recently installed rainwater harvesting system at the primary

school. The project addresses a pressing regional need with a sustainable, and proven,

solution. Additionally, rainwater harvesting has clear support from the community

members. During women’s group meetings, it was the favored solution to water needs

problems, the community water committee favors this solution, and additionally rainwater

harvesting was recommended by World Vision and the Lwengo District water engineer.

A rainwater harvesting project was chosen after a careful alternatives analysis,

based on nine different factors: accessibility, community support, cost, equity, availability

of materials, sustainability, health and safety, maintenance, and efficacy. We compared

five different project options, focusing on the communities top priority of water access.

Using a decision matrix, a borehole system scored 40, a distribution system scored 39, a

surface water retention system scored 54, and shallow water wells scored 45.5. The

household rainwater harvesting system scored highest, at 66.5.


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4.0 FACILITY DESIGN

4.1 Description of the Facilities These facilities will consist of gutters, a first flush system, and a tank

installed on individual houses with the tank located besides the house. Basic

gutters will be made from folding 1/8” sheet metal. They will be hung from the

roofs using straps cut from the same sheet metal. The gutters will funnel into a

first flush system before entering a ~2000L tank. Detailed designs and

descriptions can be found in the report below. We are presenting three

preliminary tank designs which will be further refined based on feedback from the

community collected in an upcoming assessment trip. These tank options are

Ferro-Cement, poured concrete, and block tanks.

The Ferro-Cement tank will be supported by a circular base made with

brick and poured cement. Both the pipe connecting the spigot to the hose and

the wire spokes connecting the jar to the base will be embedded into the

foundation. It will be constructed over a removable mold, as described below,

with two layers of plaster, a wrap of chicken wire, and then another two layers of

plaster to form the tank walls. Another set of wire spokes will be used to form a

lip at the top of the jar where the opening is. The spokes will be used to support

the lip molds and once these are set, the cement will be poured on top. The jar

will cure for approximately two weeks, during which time it will be covered to

protect it from the environment. This is a design which was proven widely

effective and cheap and which quickly became common practice when it was

introduced into Thailand in the 1990s, and therefore this style of design is also

often referred to as a ‘Thai Jar’.

The poured concrete tank is a 2000L cylindrical tank resting on a base.

The tank will consist of poured concrete reinforced with Gauge 3 rebar. The tank

will be 64 inches tall, 4.7 inches thick with an inside radius of 28 inches. The tank

will have a lid of two overlapping pieces of corrugated steel. The spigot of the

tank will be located on the side of the tank, 3 inches from the bottom.

The cinder block tank will have dimensions of 76”x56”x64” on the exterior

and 48”x40”x64” in the interior. It will be made of cinder blocks that are 8”x8”x16”,

staggered and mortared together, set on a concrete base. The tank and the base

will both be reinforced with rebar. The interior of the tank will be sealed. The

spigot will be custom-made in one of the blocks in the second layer of the tank,

the water inlet will be in a block on the top of the tank, and the overflow will also

be drilled into one of the blocks on the top row of the tank. The lid of the tank will

be made of corrugated metal, and will be removable for maintenance.


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4.2 Description of Design and Design Calculations

4.2.1 Gutters and First Flush System

The team evaluated multiple options for the gutters. The primary concerns were

robustness, durability, and price. The options considered were 4” PVC gutters, pre-

fabricated aluminum gutters, and hand folded V-shaped 1/8" sheet metal gutters.

PVC was found to be prohibitively expensive in Uganda, and the nearest supplier

is 35 km from Bugonzi. It is also heavier than the other options and the structural stability

of the roofs is not high. Pre-fabricated aluminum K-style gutters with an attachment to a

fascia board was also considered were prohibitively expensive as wood is very

expensive in Uganda. Also,the variability in the trusses on household roofs to which the

fascia board would be attached also means that ease of installation cannot be ensured

with this option.

The problems with these two considered options has led to our current design for

the gutters, of hand folded V-shaped gutters made of 22 gauge Galvanized Steel.

Galvanized steel is tough, flexible, corrosion-proof, and available in country. This design

will be edited and further detailed for each house chosen to be part of our initial

implementation, taking into account roof conditions and materials.

4.2.1.1 Gutter Attachment

The gutters will be directly suspend from the roof. A 2in x 2in wide band

will wrap around the gutter and be attached to the corrugated roof by two ¼ inch

bolts with washers. Holes will be punched into the roof and then two 3in long ¼ in

inch diameter bolts will be screwed in to hold the band in place. The bands will

have different lengths because the gutters will have a 1% slope so that they can

drain into the first flush and then into the tank. Along with the bands the gutters

will be held up by rebar with each band as support. The drop of the gutter system

to reach a 1% slope will be an average of 3 inches. This is calculated for the

average roof size of 25’x12’. For drawings and calculations regarding the force

on the gutter and the rebar support, see Appendix A.4 Gutters and Piping

Calculations.

4.2.1.2 Gutter Specifications

The gutter will have an opening width of 7” and a depth of 5”. We decided

on this dimension due to the rainfall average (Appendix C). 12in wide sheets can

be bent at the midline to make this shape. Since sheets are sold in 5’ long

sheets we will need 12 sheets total per house. The sheets will overlap on the

ends by 2” and will be bolted near the top, along with being supported by the

bands that attach the gutter to the roof. Although the band will not be at every

overlap on the gutters, the support from the bolts will prevent the force from the

water on the gutters from causing them to break apart (Appendix A.4 Drawing

1.2) Since the gutter is in a “V” shape we will be designing end caps with excess


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sheet metal. The strips will be cut into a triangle shape with tabs, that will then

be folded in. Silicone sealant and bolts will also be used to keep the water from

leaking out of the end (Appendix A.4 Drawing 1.3).

4.2.1.3 Transfer to First Flush

To transfer the water from the gutters to the PVC first flush system, we

will cut a 4” hole in the bottom of the gutter towards the tank side of the house.

The hole will then have a galvanized steel funnel that will lead from the hole to

the opening of the PVC that heads to the first flush system. The funnel will be

sealed and bolted just like the end cap of the gutter, with silicone sealant and

bolts.

4.2.1.4 First Flush

The water will immediately enter the first flush system after it comes from

the gutters. A calculated 1.5 gal will need to be eliminated to rid water of debris

as calculated from the University of Arizona Cooperative Extension Water Wise

Program. This states that the first 10 gal of the first 1000 square feet will

eliminate any unwanted debris. As calculated from the average roof size, the first

flush system needs to be 2.3 feet long and 4” in diameter. This includes a wye

PVC Joint, a coupling, and Female and Male PVC (for drainage). The system will

use the ball on string method to prevent the debris from floating to the top of the

first flush system and draining into the water storage tank. The ball and string will

be attached to the female and male PVC so that it can be cleaned and replaced

when the user empties the first flush system after a rainfall. The first flush will be

supported by a 4”X4” post that will be cemented into the ground. The first flush

will then be strapped to the pole using the same galvanized steel strips as the

attachment to the gutters to the roof (See Appendix B.4 Figure B.4.3) . For

calculations used to determine the length of the first flush, see Drawing 1.4 in

Appendix A.4.

4.2.1.5 Transfer from First Flush to Tank

When the first flush is full, the water level in it will push the ball to the top of the

downward oriented pipe, making the pipe flowing towards the tank continuous

again. This will allow the water to flow over the first flush and continue on its way

down the 4” pipe. This pipe will run directly into the tank. The pipe running from

the first flush to the tank will be supported by 4”x4’ wooden beams that are

cemented into the ground along its way. The 4” pipe will then be cemented into

the top of the roof of the tank. The 4” pipe will be at a 1% slope from the first

flush to the tank.

4.2.2 Tank Design Option One: Block

The block tank will be built out of cinder blocks with dimensions 8 inches by 8

inches by 16 inches. The tank will be 8 blocks tall, 4 blocks long and 3 blocks wide so it


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will be 76”x56”x64” on the exterior and 48”x40”x64” in the interior. It will be able to hold

about 2,000 liters of useable water. The tank will be set on top of a concrete slab. This

concrete slab will have a rebar mesh with 12 inch spacing between the bars in each

direction. L-shaped rebar will be set into the concrete around the perimeter, and the first

layer of blocks will be placed on these bars. The walls will then be constructed by

staggering the blocks and mortaring between them. Rebar will be set in the holes

through each block from the top to the bottom of the tank to stabilize the structure. The

holes will then be filled with concrete. The interior of the tank will be sealed in two layers.

As part of the first layer, a mix of sealant and mortar will be smoothed over the blocks.

The second layer will be a paint-on sealant.

The spigot for the tank will be custom built into one of the blocks by a local block

maker. This spigot block will be built into the bottommost course of blocks. The lid for the

tank will be made out of a sheet of metal. This sheet will be attached to the tank by bolts

set into the concrete in the block holes, and it will be removable for maintenance of the

tank. The water inlet will be drilled through a block in the top row of the tank. PVC pipe

that drains the gutter system will be set into this hole. An overflow hole will be drilled into

the bottom of one of the bricks in the top row. For further calculations, see Appendix A.3

starting on page 36.

4.2.3 Tank Design Option Two: Poured Concrete

This preliminary tank design aims to create a poured concrete tank for holding

rainwater. The cylindrical concrete tank will be able to hold 2,000 liters of accessible

rainwater. It will be 64 inches tall, 4.7 inches thick, and have an inside radius of 28

inches. It will have a drainage pipe with a spigot 3 inches from the bottom of the tank.

The bottom 3 inches of the tank will allow for the settling of particles. A small depression

will be dug in front of the spigot to allow for easy access. The tank will have an overflow

hole 4 inches from the top. The top of the tank will be covered with two overlapping

pieces of corrugated steel. The steel pieces will be pushed into the wet concrete to

create a mold for them to rest in. Bolts will be pushed into the wet concrete. When the

concrete cures, the steel plates will have holes drilled into them so that they fit on the

bolts and they will be fastened with nuts. The inlet pvc pipe from the gutters and the

outlet pipe for the spigot will be placed in the wall while the tank is being poured. The

tank will have vertical steel reinforcement bars every 10 inches around the perimeter (19

total bars). The bent circular horizontal steel reinforcement bars will be spaced every 10

inches with an extra circle at the top of the tank (6 total bars). The base of the tank will

have a mesh of bars spaced every 10 inches, and a circular reinforcement around the

perimeter which will be connected to the vertical bars in the cylinder. The construction

process, including a rough design of the molds, is described in the construction section

of this report. The calculations for this tank can be found in Appendix A.2.

4.2.4 Tank Design Option Three: Ferro-Cement

We have designed a Ferro-Cement tank that will be approximately 2000-liters.

We decided to go with the ‘Thai Jar’ shape, popularized in Thailand in the 1990s,


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because of the history of the success of the jar, the success of this type of tank by other

projects in the area, and the calculated stability of the Thai jar shaped compared to a

cylindrical shaped tank.

The design calculations can be followed in Appendix A.1. The base will be a

cylindrical shape with a radius of 29” and a height of 12” constructed out of layered brick

and cement. We will first level out the earth below where the tank is to be placed using

scrap metal or rebar as a mold. Then we will place the overflow pipe about 10” towards

the center of the circle. This overflow pipe will be 54” tall. We will dig a trench for the

overflowing water, it will be far enough away from the tank so the pipe can drain without

making a muddy area. After the out pipe is set, we will pour the cement into the 6”

circular mold. We will surround the outside of this mold with bricks and stones, to act as

a support for not only the tank, but also the spigot. The spigot will be 1.5” in diameter

and will exit the tank on the bottom. Connected to the spigot pipe will be a rubber hose

attached to a water bottle that is set to a buoyancy that is 5” from the surface of the

water. This buoyancy will reduce the amount of contaminants, such as leaves and other

debris, entering the spigot PVC.

On the top of the base we will crosshatch the cement so that when the tank is

built on top there will be more friction and connecting support between the tank and the

base. We will then construct the Thai Jar, first by placing rebar molds covered in burlap

sacks, approximately 3” inwards from the outside of the base’s radius of 29”. The height

of the tank will be 55”, the largest diameter, towards the top of the tank, will be 62” and

the opening on the top will have a diameter of 24.25”. Next, we will place mud slurry on

the burlap sacks to act as a release agent for when we need to remove the molds from

the fully constructed jar. After, we will plaster on the first two layers of plaster to the tank

mold ,each with a thickness of ½”. On each layer we will scratch the plaster to create a

tighter bonding seal with the next layer.

When the second (outer) layer has hardened to a leather-like toughness, we will

wrap the jar with chicken wire starting from the bottom and winding up towards the top.

Once the chicken wire is on we will plaster the tank with two more layers of ½” thickness

with scratches in between once again. We will then place multiple 2” wire spoke

segments at the top of the tank to construct a lip for the lid of the tank. We will place the

lip molds on the top, pour the plaster around it, and then let it sit to harden. Finally we

will cover the jar to allow it to dry without obtaining surface flaws from the environment.

We will check it twice a day to fix any cracks or fractures that pop up over the two week

curing time.

4.3 Drawings See appendix of drawings, Appendix B.


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4.4 Names and Qualifications of Designers

Name Student or Professional

Qualifications Work Done

Jane Dupay Student 2nd Year Mechanical Engineering

Ferro-cement tank Design, Gutter and First Flush Design

Jordan Gustafson Student 2nd Year Electrical Engineering

Ferro-cement Calculations

Roland Welter Student 3rd Year Math/ Physics

Design work for concrete and block tank

Laina Breidenbach Student 3rd Year Civil Engineering

Some calculations and design work for concrete and block tank

Arturo Schultz Professor Civil Engineering Ph.D.

Some calculations for concrete tank

Reed Saunders Student 2nd Year Mechanical Engineering

Calculations and design for block tank

John Bartoletta Student 2nd Year Chemical Engineering

Drawings for the concrete tank

Stephanie Vogeli Student 2nd Year Biomedical Engineering

Tank size calculations

5.0 PROJECT OWNERSHIP

The individual households that have a rainwater harvesting system will have

ownership of their system and will be responsible for operation and maintenance. The

systems will be located on their homes and land, and as such can be owned by these

individuals in the community. The households that are part of the initial implementation

will give their time for training in maintenance and operation, labor on the rainwater

harvesting system for the Bugonzi primary school, labor on the harvesting system on

their home, and will significantly contribute to the cost of their system. The exact

payment amount is still to be decided on, after further discussions with community

members and URF during the January assessment trip. These contributions will help to

ensure that the individual households are willing to work for their systems and will take

full ownership of them.


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6.0 CONSTRUCTABILITY Professional masons will be hired to work alongside our team during our stay in

Bugonzi. During our assessment trip we will be identifying these professionals and

laborers that are willing to learn the process of making our tanks. Using local

construction will help the community because then they will be able to continue to build

systems like these on their own once we are gone. Our role during our visit will be to

oversee as well as participate in the construction of multiple systems. General laborers

may also be used. The equipment needed during the construction process include will

include materials that are available in the nearby communities. More specific

construction plans for each aspect of the system can be found below. A specific

construction schedule for the implementation trip will be created after the designs are

finalized for the 525.

6.1 Gutters and First Flush

The gutters can be made by folding the sheet metal. This can be accomplished

by a number of methods, including lining them up beside a square block and hammering

them into the fold until they are correctly folded to match the gutter design. On a

previous trip, the proposed metal sheeting was tested and easily bent by hand. Metal

sheet bands can be cut from the sheet metal for use hanging the gutters. Once the holes

have been drilled into the roof, the gutters can be suspended.

The first flush construction can follow the method outlined below. PVC pipe can be run

between the first flush/gutters and the tank.

a. Seal the Wye PVC elbow to the PVC pipe.

b. Attach a coupling to the end of the PVC pipe where the female and male PVC is

then attached and sealed.

c. Attach a string through the end cap of the pipe and to the ball. This will need to be

inside of the first flush system.

d. Line up the funnel to the top of the Wye PVC elbow and attach.

6.2 Tanks Design Option One: Block

The block tank will be built out of cinder blocks with dimensions 8 inches by 8

inches by 16 inches. The tank will be 8 blocks tall, 4 blocks long and 3.5 blocks wide.

The first part of construction would include site preparation. This includes leveling and

sand backfill The rebar mesh, with 9 inch spacing between the bars in each direction,

would be laid on chairs first and then the concrete would be poured. L-shaped rebar will

be set into the concrete around the perimeter, and the first layer of blocks will be placed

on these bars once the base has set. The walls will then be built by staggering the

blocks and mortaring between them. The spigot for the tank will be custom built into one

of the blocks by a local block maker. This spigot block will be built into the bottommost

course of blocks. Once all the blocks are mortared in place, rebar will be set in the holes

through each block from the top to the bottom of the tank to stabilize the structure. The

holes will then be filled with concrete. The interior of the tank will be sealed in two layers.

As part of the first layer, a mix of sealant and mortar will be smoothed over the blocks.

The second layer will be a paint-on sealant.


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The lid for the tank will be made out of a sheet of metal. This sheet will be

attached to the tank by bolts set into the concrete in the block holes. The water inlet will

be drilled through a block in the top row of the tank. PVC pipe from the gutter system will

be set into this hole. An overflow hole will be drilled into the bottom of one of the blocks

in the top row.

6.3 Tank Design Option Two: Poured Concrete

A drawn representation of the construction process for this tank can be found in

Appendix B.2 starting on page 44. The outer mold will have an inner radius (that is, not

counting the thickness of the metal) of 32 inches and will be 67 inches tall. It will be

made out of metal and have lips on both sides with which we can screw the two pieces

together. It will have holes in it on the sides for the PVC pipes. On one side we will

have two holes, one having its bottom 8 inches from the bottom of the outer mold and

the other having its bottom 59 inches above the bottom of the outer mold. The other

side will have one hole with its bottom 59 inches above the bottom of the outer mold.

The inner mold will have an outer radius (that is, counting the thickness of the

metal) of 28 inches and will be 62 inches tall. It will be made out of metal.

We will use molds to pour the concrete. Before the pouring process, the molds

will be coated with oiled paper so that they may be recovered after the concrete dries.

The outer mold will be screwed together and the PVC pipes inserted into the mold as in

drawing (1). Then the rebar will be set up in the outer mold. The concrete will then be

poured into the outer mold to the desired thickness of the base as in drawing (2). We

will then insert the inner mold as in drawing (3). We will then pour the concrete into the

gap between the inner mold and outer mold as in drawing (4). After the concrete

hardens we will slide the inner mold out and unscrew and remove the outer mold as in

drawing (5).

6.4 Tank Design Option Three: Ferro-Cement

The general construction process of a Ferro-Cement tank is as follows: First, we

would pour the base into a mold, wait for it to set, and then assemble the rebar/burlap

mold. We would then spread the first two layers of plaster on the mold and wrap the jar

in chicken wire in one day. The next day we would cover the chicken wire with the last

two layers of plaster and add the top for the rim. The next day, after letting the concrete

harden, we would cover the jar with a tarp or more burlap as it cures. The estimated cure

time is about two weeks based on the thickness and average cure times for concrete.

The rebar mold can be removed and reused.

7.0 OPERATION AND MAINTENANCE 7.1 Operation


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The owners of the homes will maintain the rainwater harvesting system. Those

workers who are hired during the initial implementation will also be educated in the

proper cleaning and repair techniques by working alongside our team during the building

phase, and as such will be able to work on any larger-scale repairs that may be required.

We have designed our tanks so that they are financially possible for community

members to use our design after they have been introduced to them during the initial

implementation, and as such EWB will not be contributing to maintenance costs. Each

household will be responsible for the yearly operation and maintenance cost associated

with their rainwater harvesting system. They will assist in the building of the systems on

their homes so that they fully understand the components needed to run the system.

During the implementation trip, each household will be instructed further on maintenance

requirements for their system. The most common maintenance that the systems will

require is an emptying of the first flush system and cleaning of the gutters, which

requires no cost. If replacement parts are needed, they can be obtained in Uganda.

Replacement or repair components of the system may include, 4”x10’ PVC Piping,

(estimated 16,300 UGX per unit), 12”x18” Galvanized Steel Sheets (estimated 11,200

UGX per unit), Block (estimated 2,200 UGX per unit), concrete plaster (estimated

246,4000 UGX per cubic yard), or rubber hose (estimated cost 5,000 UGX per unit) and

can be obtained near Bugonzi. Further material costs will be gathered during the

January assessment trip to ensure that the system is kept as low-cost as possible. Large

repairs needing these components should be infrequent.

7.2 Maintenance

A detailed and complete training and instruction manual will be written and

provided for the owners of each tank. Extra copies will be kept with URF. The manual

will include procedures for the maintenance checks that will be performed by the owners

or hired professionals. Parts will be indicated pictorially for ease of reference during

maintenance and replacement. A detailed and thorough checklist will be drafted and

translated. This will assist the operations manager with the identification of potential

system failures as well as ways to go about resolving the issue. Maintenance will also be

addressed extensively during the education portion of our implementation trip.

8.0 SUSTAINABILITY

For this project, each household system must be maintained in order to produce

optimal results. The gutters will need to be kept clean of debris such as organic material

and dirt accumulation. A first flush system will be implemented, this system will need to

be emptied in order to work properly during the next work cycle. To prevent unwanted

organic growth the reservoir should also undergo periodic cleaning.


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8.1 Gutter Sustainability

The sustainability of the gutter system is a function of both the gutter materials

chosen and the quality of the material obtained. The gutters for this system will be built

from 22 gauge galvanized steel, a tough, flexible, and corrosion-proof material.

Barring excess loading and gross mistreatment, it is expected that this material

will provide a long working life. Due to the vertical offset of this system component, it is

expected that most damage would be incurred by ladders coming into contact with the

system. Due to the relatively low annual maintenance, it is expected that this will not

present much of an obstacle. The gutters will be purchased from a local manufacturer

and supplier as close to Bugonzi as possible. Due to the combination of local availability

and favorable material properties it is expected that the gutters will be a sustainable

system component. Other factors which may affect the sustainability of the gutters, such

as the roof conditions, will be assessed during the January assessment trip.

8.2 First Flush

All PVC pipes and fittings will be purchased locally. Downspouts and 4.3 inch

material will need to be purchased in Kampala (5 hour drive, but it can be ordered from

vendors in Masaka (1 hour drive). Failure of this system component would most likely be

due to misuse of the system, such as being used as a climbing aid. Due to the local

availability and the strength of PVC, this component of the system is not expected to

break unless mistreated in some way.

8.3 Tank Sustainability

Reservoir tanks for this project will be constructed of either concrete or cinder

block. The tank will be subject to negligible photo-degradation compared to other

common materials such as plastic. A thick concrete and brick foundation is very durable

and will reduce the dangers of tank degradation due to shifting ground. By properly

preparing the work site stability concerns can be minimized as well. Maintenance of a

brick and concrete tank will be easy to carry out and will primarily involve patching with

plaster if leaks develop. Periodic cleaning of the inside of the tank will also be necessary.

This process is facilitated by the dry seasons, when the tank will be relatively empty.

Patching is a relatively simple and non-specialized task which can be accomplished by

the homeowners. An access point for service will be included for easy access to the

interior of the tank. Further factors which may influence the tank sustainability, such as

the soil conditions, will be assessed during the January assessment trip.

9.0 MONITORING 9.1 Monitoring plan for current project

The current conditions within the community will be assessed in order to

stand as a standard against which we can compare the effects of our project


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once it has been implemented. These conditions will be measured using several

matrices, as outlined below.

Matrix Data to Be Collected Measurement Method

Water availability Average distance traveled and

time spent to collect water

Survey of Community members

Transference The number of households

which have systems and the

number of households which

wish to have systems

Survey of Community members

and assessment throughout the

community to locate the various

systems

Wants/ Expectations The satisfaction of each families

water collection method will be

rated and compared pre and

post implementation

Survey of community members

(With ranking of satisfaction)

10.0 COMMUNITY AGREEMENT/CONTRACT

Though not yet completely finalized, this is the current Community

Agreement/Contract for the implementation of Household Rainwater Harvesting systems

in Bugonzi. This agreement may be modified in the future to reflect discussions between

the various partners prior to actual implementation.

Memorandum of Understanding

Household Rainwater Harvesting Systems in Bugonzi

This contract is between the leaders of Bugonzi, the pilot households, Uganda

Rural Fund (URF), and the University of Minnesota Chapter of Engineers Without

Borders-USA for the purpose of setting guidelines and expectations for the

implementation of Rainwater Harvesting Systems in Bugonzi.

Uganda Rural Fund agrees to provide:

· Breakfast, lunch, and dinner for the EWB volunteers (in return for $7/day

per person from EWB)

· Housing for the volunteers

· Transportation each morning to Bugonzi and each evening from Bugonzi

back to the housing

· At least one English-Luganda translator each day

· A location where supplies can safely be stored


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· An attitude of positivity and helpfulness

· Diligence for the safety of all the parties involved

· Assistance with purchasing of supplies

University of Minnesota EWB-USA agrees to provide:

· Money and logistical support for the sourcing of concrete, bricks,

equipment, sheet metal for gutters

· Labor

· Time sourcing water for Construction

· Experience and knowledge relating to this project

· Plans for the implementation and building of the rainwater harvesting

systems

· A diligent awareness of safety for all involved

· Education on maintenance and construction of the rainwater harvesting

systems

The households receiving systems agree to provide:

· Maintenance for the harvesting systems in the future

· Whatever building equipment they already own

· A prepared tank space meeting the specifications set by EWB directly

adjacent to the house

· A safe storage location for the materials and equipment

· Experience in local building techniques and customs

· Labor from household members

· Awareness of everyone’s safety

· Willingness to learn and be educated on the rainwater systems as well as

a willingness to educate other community members after EWB has left

· Positive attitudes

· The funds paying for the portion of the rainwater system as set by EWB

The community of Bugonzi agrees to provide:

· A community liaison between the EWB volunteers, the individual

households, and community in general, in the form of the Water

Committee

· A guarantee of the safety of materials and supplies stored in Bugonzi

· Awareness for the safety of all involved in the project

· Positive attitudes

· A warm welcome to the EWB volunteers

On behalf of the community of Bugonzi, the NGO Uganda Rural Fund, and the

University of Minnesota chapter of EWB-USA the under-signed agree to abide by the

above conditions.

John Mary Lugewa

Stephanie Vogeli

Leader of Bugonzi

Household Members


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11.0 PROFESSIONAL MENTOR/TECHNICAL LEAD ASSESSMENT 11.1 Professional Mentor/Technical Lead Name

Jeff Weiss

11.2 Professional Mentor/Technical Lead Assessment

I have been working with the Ugandan rainwater harvesting system since

January, 2012. This last September, the team assessed their tank design and

chose to reevaluate all possible concepts to identify one that would be easier to

implement in-country. I was in support of this course of action and believe that

they took a more realistic approach to what they could accomplish in a short time

frame. The team has narrowed the possible tank designs down to three options

and will be finalizing the design based on the feedback of the January 2013

assessment trip to be conducted by Stephanie Vogeli and Jane Dupay. This

assessment trip will be critical to the final design as they evaluate material

availability, local labor skills, house design factors, and community acceptance of

the three designs. I believe that the result of this work will be a system that can

be implemented by the EWB team and will meet the needs of the Bugonzi

community.

11.3 Professional Mentor/Technical Lead Affirmation

I affirm that the designs and plan outlined in this document have been

developed with my involvement and I fully support it.


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APPENDIX

Appendices for EWB-UMN Household Rainwater Harvesting System for Bugonzi, Uganda Table of Contents page Appendix A: Calculations 30 A.1 -- Ferro-Cement Tank 31 A.2 -- Poured Concrete Tank 34 A.3 -- Block Tank 36 A.4 -- Gutters and Piping 37 Appendix B: Drawings 40 B.1 -- Ferro-Cement Tank 42 B.2 -- Poured Concrete Tank 45 B.3 -- Block Tank 49 B.4 -- Gutters and Piping 52 Appendix C: Tank Size Decision 55


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APPENDIX A: Calculations


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APPENDIX A.1: Ferro-Cement Tank Calculations


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APPENDIX A.2: Poured Concrete Tank Calculations


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APPENDIX A.3 Block Tank Calculations

The interior of the tank will be 56 inches wide, 40 inches long, and 64 inches tall. In metric, this is 1.42 meters by 1.02 meters by 1.63 meters. Therefore the interior of the tank’s volume is 2.35 cubic meters, or 2350 liters. The tank is designed to hold 2000 liters of water plus extra room for any sediment left over from the first flush. The distributed pressure load [N/m2] against the inner wall of the block tank due to the

water is

Here [N/m3] at 30°C, and [m] is the height of the water in the tank. An

approximately rectangular segment of the wall is selected with height = [m], the total

height of water in the tank when full, and base = [m]. The base is some small,

arbitrary length. The pressure force [N] is

This force acts at a distance of [m] from the bottom of the tank. The moment

reaction at the base of the tank [N·m] is then

The tension stress in the reinforcement [N/m2] due to this moment is

This stress must be less than or equal to 137,895,146 [N/m2] for reinforcement. For a tank water height of 1.63 [m],

So the 8 inch thick walls with reinforcement will be suitable for withstanding the water pressure that the tank will be subjected to.


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APPENDIX A. 4: Gutters and Piping Calculations


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APPENDIX B: Drawings


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Drawings for the 524

University of Minnesota

Household Rainwater Harvesting Systems

Bugonzi, Uganda

INDEX OF DRAWINGS

Ferro-Cement Tank drawings pg. 42 Poured Concrete Tank Drawings 44 Block Tank Drawings 48 Gutters and Piping Drawings 51


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APPENDIX B. 1: Ferro-Cement Tank Drawings


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APPENDIX B.2: Poured Concrete Tank Drawings


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APPENDIX B.3: Block Tank Drawings All dimensions in inches unless otherwise noted.

Top view of the tank


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Side views of the tank


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Cross section of the tank viewed from top (above drawing), side view of tank (bottom left), and cross section of the tank viewed from the side (bottom right)


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APPENDIX B.4: Gutters and Piping Drawings Figure B.4.1 -- The gutters will be made of Galvanized steel and be hung from the roofs of the houses by strips of the steel sheeting.


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Figure B.4.2 -- Above shows a cross section of the gutter.


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Figure B.4.3 -- This drawing illustrates where the gutters will be attached on the roof of the house, and how they will connect to the first flush system and the tank.* *Note that a generic tank design was chosen to show how it will enter. This tank does not represent any of the tank options presented above.


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APPENDIX C: Tank Size Decision


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APPENDIX C: Tank Size Decision The tank size chosen for this project is 2000 liters. This decision reflects the average amount of rainfall per month, average roof size, and average water consumption per household. Assumptions:

Roof Size: Of the 16 houses who applied for systems, 8 gave the dimensions of their homes.

Areas (sq ft)

600

440

660

924

315

396

216

300

Average: 481.375

The average area of the roof for the reported houses is 481.375 feet squared.

As such, an average roof size of 480 square feet was used in our calculations. Rainfall: Methodology: 1) Found available weather data from relevant Uganda weather stations. 2) Since the project location is in a relatively dry area of Uganda, locations such as Entebbe, Kampala, and Masaka were disregarded since the shores of Lake Victoria are high rainfall areas. 3) Generally higher elevation stations were chosen, matching our location. 4) To ensure that the result is conservative, all the results were compiled below, and the lowest reported rainfall for the month was used in calculations. Compilation of Data from Station, measured in cm:

January February March April May June July August September October November December

3.9 8.4 17.1 28.2 14.7 6,9 5.1 9.3 9 10.5 11.4 8.7 cm

5.7 6.3 11.7 17.9 16.7 4.1 3.7 5.4 8.7 10.1 10 8.7 cm

2.4 * 11.1 * 4.8 * 21 * 12.6* 21 * 3 * 12 * 25.5 * 18.9 * 21.6 * 3.3 * cm


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5 6 10 13 8 3 2 6 9 11 13 7 cm

6 8 10 14 10 3 2 4 9 9 11 9 cm

Note: *indicates potentially suspect data set The highlighted March 4.8cm rainfall value is assumed to be an error in the dataset and was discarded. The second lowest data point, 10cm, was used instead. References:

1) http://www.worldweatheronline.com/Bugonzi-weather-averages/Mpigi/UG.aspx 2) http://www.weatherbase.com/weather/weatherall.php3?s=637051&refer=googlee

arth&cityname=Masaka-Wakiso-Uganda&units=metric 3) http://www.meoweather.com/history/Uganda/na/1.1333333/31.3166667/Masaka.

html 4) http://www.weather-and-climate.com/average-monthly-precipitation-

Rainfall,Mbarara,Uganda 5) http://www.weather-and-climate.com/average-monthly-Rainfall-Temperature-

Sunshine,Kabale,Uganda

Compilation of the lowest rainfall data (to be used for calculations):


2.40 6.00 10.00 13.00 8.00 3.00 2.00 4.00 8.70 9.00 11.00 3.30 cm

Comments:

Isopluvial map indicates 760 to 1030 mm annual rainfall for project area, with the project location about mid-way in the range area.

The selected values above result in 752 mm rainfall, giving a likely somewhat conservative result.

Using this conservative rainfall estimate, we are ‘padding’ our results somewhat, so that the actual amount of water they will be able to use will likely be more than what we calculate.

Resulting Data set graph shape is reasonable in shape when compared to other data set graphs and known features of Uganda weather with 2 dry and 2 wet seasons.

http://www.worldweatheronline.com/Bugonzi-weather-averages/Mpigi/UG.aspx

http://www.weatherbase.com/weather/weatherall.php3?s=637051&refer=googleearth&cityname=Masaka-Wakiso-Uganda&units=metric

http://www.weatherbase.com/weather/weatherall.php3?s=637051&refer=googleearth&cityname=Masaka-Wakiso-Uganda&units=metric

http://www.meoweather.com/history/Uganda/na/1.1333333/31.3166667/Masaka.html

http://www.meoweather.com/history/Uganda/na/1.1333333/31.3166667/Masaka.html

http://www.weather-and-climate.com/average-monthly-precipitation-Rainfall,Mbarara,Uganda

http://www.weather-and-climate.com/average-monthly-precipitation-Rainfall,Mbarara,Uganda

http://www.weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,Kabale,Uganda

http://www.weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,Kabale,Uganda


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Water Consumption:

All data collected from the community regarding household water use has been vague and not consistent. For instance, a household with 2 people would report using only 2 jerry cans of water less per day than a household of 13 people, and other inconsistencies of this type. Therefore, water data from the World Health Organization (WHO) was used for our estimation.

The WHO says that the people need 7.5 liters per capita per day. Household size in Bugonzi ranges widely, but we estimate that the average size if approximately 8 people per household.

Calculate: 7.5 x 8 = 60 Therefore, our calculations use an estimated 60 liter per day consumption per household. Calculations:

Methodology: 1) Assume the tank is dry at the end the first January and calculate 1 year from there. 2) Calculate the level of water remaining in the tank each month for several years until it "stabilized". 3) Using the following values:

Roof Area: 480sq ft. Daily Consumption: 60 liters Days/month: 30 Proposed Tank Volume: 2,000 liters The above monthly rainfall data chart.


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Calculations: Monthly Rainfall (liters) based on roof area


1,070

2,676

4,459

5,797

3,567

1,338

892

1,784

3,880

4,013

4,905

1,472

Monthly Net water flow into tank (rainfall minus consumption):

Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec

-730 876 2659 3997 1767 -462 -908 -16 2080 2213 3105 -

328

(Negative numbers mean more usage than accumulation for the month) Average Net monthly Inflow: 1188 liters Water Volume in Tank Calculations:


0 876 2000 2000 2000 1538 630 613 2000 2000 2000 1672 1st yr

942 1817 2000 2000 2000 1538 630 613 2000 2000 2000 1672 2nd yr

942 1817 2000 2000 2000 1538 630 613 2000 2000 2000 1672 3rd yr

942 1817 2000 2000 2000 1538 630 613 2000 2000 2000 1672 4th yr

942 1817 2000 2000 2000 1538 630 613 2000 2000 2000 1672 5th yr

Note: To ensure year-round availability, no value may be less than zero, and the cycle must stabilize. With the tank value of 2,000 liters, this cycle stabilizes and does not equal 0 any month, and as such a tank value of 2,000 liters is appropriate.

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