MAGAZINE TYDSKRIF

IRRIG

ATION

BESPROEI

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MAGAZINE TYDSKRIFTHE MAGAZINE FOR THE SOUTH AFRICAN IRRIGATION INDUSTRY • DIE TYDSKRIF VIR DIE SUID-AFRIKAANSE BESPROEIINGSBEDRYF

Volume 9 • Issue 4 • SABI | APRIL/MAY 2017

ISSN 2071-1883

Irrigated agriculture’s extent in South Africa

Sustainable development goals

Green consciousnessHydropower blooms

San’s Ethics Code for researchers

Pumps, valves and pipes show

Climate change

Victory in SA’s first climate change court case 4

Research

Extent of irrigated agriculture in SA: a new status quo? 6

San Code of Ethics launched 14

Sustainable Development

Goals! Affluence Lite, no poverty 15

Pumps, valves and pipes show

Indutec 2017 in Midrand in May 11

KSB in Zambia 12

Dawn helps Wolf Sanctuary with water 13

News

Massive investment in hops in George 18

Sunnyside up – after the drought 29

Energy

Hydropower in agriculture blooms again 20

Energy from biogas and organic waste boosted 23

Energy and your operation 30

Biofuels, the potential of papyrus wetlands in Africa ccc

How To…

How to select and install pipe flanges 26

Agriculture

Need to pull together: key role players 34

Macadamias, bats control pests 36

SA entrepreneur wins Agripreneur of the Year 38

Innovations

Trench digging 43

Regulars

From the editor 2

President’s message 3

Company members 24-25

Weather 40

Dam levels 41

SABI Approved Designers 46

Training Update 47

Subscribe now 47

Advertisers contents 48

Diary 48

Contacts at SABI 48

contents

Pg4

Pg6

Pg15

Pg20

Pg26

Pg36

CONTENTS

Carol [email protected]

Riana [email protected] Sales

René van der [email protected] and circulation

Isobel van der [email protected] Executive Officer

Annemarie van der [email protected] Assistant

Liam [email protected] | alliancephoto.comGraphic Design

Contributors: Ian de Jager; Mike de Villiers; Gareth Gregory, Caren Jarmain, Adriaan van Niekerk, Jascha Muller & Ruben Goudriaan, The Conversation.

PrintingColourtone Aries, Cape Town, RSATel: +27 21 981 8873

DistributionEzweni Magazine Distributionwww.ezwenimags.co.za

Media Support www.mediasupport.co.za

Cover PhotographL’Ormarins hydropower construction by I&F Engineering in action

Published by SABI (South African Irrigation Institute / Suid Afrikaanse Besproeiingsinstituut)T: +27 21 850 8220 | E: [email protected]

Web: www.sabi.co.zaAddress: PO Box 834, Strand, 7139, Western Cape, South Africa

SABI magazine / tydskrif is a bi-monthly publication.

© Copyright: South African Irrigation Institute/Suid-Afrikaanse Besproeiingsinstituut) (SABI). Requests to reproduce material herein should be addressed to [email protected].

All rights reserved. Disclaimer: The views expressed herein by authors or advertisers are not necessarily subscribed to or endorsed by SABI or the editor.

SABI | APRIL / MAY 2017 1

SABI | APRIL / MAY 20176

Extent of irrigated agriculture in South Africa: the new status quo?

by Caren Jarmain, Adriaan van Niekerk, Jascha Muller and Ruben Goudriaan

This past year South Africa has been in the grip of a severe drought – some areas have been experiencing these conditions for more than two years. As a consequence, large areas under rainfed agriculture have been greatly affected. Many irrigated areas have also been affected adversely, resulting in water conservation measures and water restrictions imposed, with water supplies

substantially cut.

Without water, no agricultural production can take place. As a result, in the midst of an extreme event, questions often arise around water management:• Do we know the extent of

irrigated agriculture? • Do we know how much

water is used by and needed for irrigated

agricultural production? • Do we know how much water

is available in different water management areas?

• Considering the uncertainties of the future: how can we empower ourselves with knowledge to ensure that we apply available water resources sustainably?

Research

1Van der Stoep I. and Tylcoat C. 2014. South African irrigation statistics – an analysis of the 2014 water registration management system (WARMS) data. SANCID 2014 Symposium, 18-20 November 2014, Glenburn Lodge, Gauteng.

2 DAFF. 2012. Abstract in Agricultural statistics. In Department of Agriculture Forestry and Fisheries (ed.).

3 Committee on food and feeding strategy. 1990. The nature, extent and potential of the natural resources of the RSA and the determining influence thereof on future agriculture development. Department of Agriculture Development. Pretoria

4 Backeberg G.R., Bembridge T.J., Bennie A.T.P., Groenewald J.A., Hammes P.S., Pullen R.A. & Thompson H. 1996. Policy proposal for irrigated agriculture In South Africa. WRC Report No: Kv96/96. Pretoria: WRC.

Available from: http://www.wrc.org.za/Pages/DisplayItem.aspx?ItemID=7961&FromURL=%2FPages%2FDefault.aspx%3F

5 Backeberg G.R. 2003. Water usage and irrigation policy. In Nieuwoudt L & Groenewald J (eds): The challenges of change. Pietermaritzburg: University of Natal Press.

6 Bastiaanssen W.G.M., Cheema M.J.M., Immerzeel W.W., Miltenburg I. and Pelgrum H. 2012. Surface energy balance and actual evapotranspiration of the transboundary Indus Basin estimated from satellite measurements and the ETLook model. Water Resources Research 48 (11). DOI: 10.1029/2011WR010482.

7 WRC. 2015. Water Research Commission Knowledge Review for 2014/15, page 160-161.

A novel approach is being developed to routinely update outdated estimates

related to South African irrigated agriculture, specifically crop water use and the

surface area utilized. This article sheds some light into recent research findings.

With the project entering its final year, feedback is being solicited.

SABI | APRIL / MAY 2017 SABI | APRIL / MAY 2017 15

Sustainability

Goals! Sustainable development goals

By Carol Posthumus

Earlier this year the 6th World Sustainability Forum (WSF 2017) was held in Cape Town with key local and international speakers including world-leading economist Professor Jeffrey Sachs, senior United

Nations (UN) advisor and director of the Earth Institute at Columbia University.

The WSF is an annual sustainability conference which addresses research in a range of areas related to sustainable development and sustainability globally. This was the first WSF to take place on the African continent. Discussions at the 2017 conference were driven by the 17 sustainable development goals (SDGs) adopted as part of the 2030 Agenda for Sustainable Development by the UN in September 2015. At the event Jeff and Sonia Sachs received the first World Sustainability Award.

Highly pertinent to South Africa with our ongoing education challenges and crises, the speakers highlighted the need for universities’ need to take the lead in solving the greatest challenges the world faces today, particularly in Africa.

They said they need to do this

not only through education – teaching the next generation to think critically and creatively to find sustainable solutions – but also through research that cuts across a range of disciplines. To ensure these solutions are implemented, universities need to partner with the private sector and with government.

SDGs a lifeline and our moonshot

Achieving the SDGs “is the moonshot for our generation,” said Sachs. “Like the moonshot [moon landing] of the 1960s, these are tough, bold and achievable objectives.”

“This is a nasty, tough world we live in, and our world agrees on very little. So when 193 governments agree on something: that is important. And when they agree on something as important

as sustainable development that is really something for us to grab hold of – that is a lifeline.”

Addressing the Forum was Foundation Global Values Alliance’s president Professor Klaus Leisinger who spoke on the topic of “Towards a new understanding of the Game, Agenda 2030 for Sustainable Development.” We met Professor Leisinger in Cape Town recently, where he was attending the San Code of Ethics launch. In addition to heading up the Alliance, Leisinger is Professor of Sociology at the University of Basel, where he pursues research and teaches a wide range of topics related to international development and health policy as well as business ethics, corporate responsibility, and business and human rights.

Leisinger says: “I have worked for nearly 40 years in the areas s u s t a i n a b l e d e v e l o p m e n t , corporate responsibilities and business ethics – so has my partner, Karin Schmitt. We have built up a global network of like-minded people and continue

to network to make the world a better place. Such a mission keeps responsible people busy as long as they are able to contribute towards this noble objective. The Global Values Alliance (www.globalvaluesalliance.ch) is a non-profit foundation that helps apply ethical norms and values in everyday practice in business, politics and society.

“We assume the advocacy for the Sustainable Development Goals of the United Nations and for an economic ethos based on intercultural, interreligious and internationally recognized values. We focus our attention on strategic research and application partnerships with organizations and institutions at home and abroad. The TRUST project (http://trust-project.eu) is such a partnership,” elaborates Leisinger.

Big changes, New Game

It appears humanity needs a new approach – a changing of the game - to solve the challenges. It is startling to consider the wholly

Hydropower potential in the agricultural sector

by Ian de Jager


Hydropower is again blooming and is just in the beginning of its cycle and there is huge scope still to be developed or upgraded, writes SABI Western Cape chairman Ian de Jager, whose engineering firm I&F Engineering has recently constructed some exciting large scale hydropower projects for renewable energy and green energy conscious farms and enterprises.

BackgroundHydropower can only be developed at specific sites. You need a flow of water, but more importantly you need a head or elevation in the flow – from a dam or mountain down to a lower elevation: this we call the “head” which will become the pressure we require before the turbine inlet.

Hydropower can be developed from any river where changes in elevation like a rapid or waterfall is present. Even a dam can present hydropower potential where a certain head is available. The flow rate of the water and the head will then determine the power (kW) that can be generated

and the flow duration will deliver the energy (kWh). The power generated depends on flow and head or pressure.

Thus power P = ρQgH

ρ = density of water,Q = flow in m³/s, 

g = gravity constant, H = head or pressure in metre H2O

The energy from a hydropower plant can be either used directly on the farm to supplement the energy drawn from Eskom to reduce costs or it can be fed into the National Grid to be used anywhere in South Africa where Eskom or a municipality delivers

energy to clients.

Due to our climate, in the Western Cape we have a different situation than in the rest of the country. When it rains in the winter – the farmers do not irrigate much as the soil is wet and the vegetation is in the rest phase. In the summer our farmers tend to need irrigation and the rain is very sporadic. This also means that when ample water is available for hydropower generation – less energy is required on the farm.

Banking energy and turbines

Luckily, Eskom appraised the situation and gave the farmers

the opportunity to bank energy in the grid over a year period to be used in the summer months. So the problem was solved. This also gives farmers in the Western Cape the opportunity to generate power in the High Demand periods from June to August when energy is more than double the cost as in the other (summer) months. The banking of energy is based on the value of the energy (kWh) and because you are banking at high value, you can utilise nearly double the energy in the summer.

Turbines are developed for the specific head and flow. For different head ranges there are different types of turbines developed for

Hydropower

I&F Engineering recently completed the 2.3 MWatt Hydropower plant at L’Ormarins, a well-known wine and thorougbred horse farm. The pipeline winds down the Hottentots Holland Mountains, the turbine building houses two Pelton turbines.

Hydropower is blossoming anew especially in the Western Cape.

How to ...

select and install pipe flanges

How to ...

Pipe systems in the irrigation sector use a number of different jointing systems dependent on the pipe material, the operating pressure of the system and the need to be able to dismantle the system for maintenance or operational reasons. Flanged connections satisfy all of the above criteria and are an essential jointing system in

the piping Industry. - by Mike de Villiers

INTRODUCTIONStandard pipe jointing systems vary from solvent cement and integral rubber ring joints in PVC, to compression and butt-welded joints in HDPE, insert joints in LDPE and quick couple joints in removable surface irrigation systems. However, when it comes to the interconnection of differing pipe and fitting materials, the jointing systems have to be compatible with each other. For example, HDPE pipes will utilise a compression male adapter to connect the pipe to say a female brass valve. The most commonly used jointing systems for interconnections in the smaller diameters are BSP threaded fittings, whereas flanged connections are used in the larger diameters. High pressure valves and pumps are usually manufactured from ductile iron, a specialised form of cast iron. The need to remove these items from the line for maintenance or replacement makes the use of flanged connections an essential feature. Flanged connections also enable the direct connection of different pipe materials to these items over a wide range of diameters.

FLANGE SPECIFICATIONS

A flange is a round piece of steel or plastic, with holes drilled around its circumference. Two flanges are used to complete a joint. They are bolted together with a rubber gasket between the faces, in order to achieve a water-tight joint. However, flanges are not that simple. Apart from the pipe diameter, one needs to consider the pressure rating as well as the flange specification, also known as the “flange drilling”.

South Africa has its technology rooted in Imperial dimensioning (inches). With the formalisation of the use of metric systems in the RSA in 1962, flange options became far more complex and we live with this history to this day. BS 10 table D flanges (Imperial dimensions) are historically very popular in the Irrigation sector, however metric flanges to SANS 1123 is the industry standard for valves and pumps in the RSA. Note that Table D flanges are pressure rated at 600 kPa (6 bar) and that SANS 1123 has tables that cover the entire pressure range up to 4000 kPa (40 bar).

Needless to say, one cannot directly connect a Table D flange to a SANS 1123 flange because of the different dimensions. Flange suppliers, however, hold stocks of blank flanges and drill these according to demand, which mitigates some of the historical preferences for imperial flanges.

The pressure rating of a flange is dependent on the thickness of the disc as well as the size and number of holes drilled in the flange. The holes are drilled to accommodate the securing bolts that, when tightened, hold the two flange faces together. The size of the bolts is a very important aspect of the flanged joint, as the bolts have to withstand the massive pressure differentials that are at play, especially in valves during opening and closing functions.

The holes are drilled around the flange in a circle and each flange size, corresponding to the pipe size, has a different diameter measured between the bolt centres. This is known as the Pitch Circle Diameter, or PCD of the flange. Some of the smaller flanges, called universal or multi-drilled flanges, are compatible with both Table D (Imperial) and Table 1600/3 (metric) flange drillings, however multi-drilled flanges have a maximum pressure rating of 10 bar. Other drilling tables are available, such as BS 4504 (Imperial) and ASME 16.5 (American) but these are not common in the irrigation sector, they may be used on some specialised equipment. The “tables” mentioned above refer to the dimensional tables contained in the flange specifications, which are shown below. The tables below show the popular flange sizes. Refer to the full tables for the complete range of flange sizes.


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