Transcript of "Water Wise Guide to Landscaping - South Africa"
Rand Water’sWater Wise Guide toLandscaping
Rand Water’s Water Wise Guide to Landscaping 1World-class Water ContentsWise landscaping 2 Landscaping for the future 3 Water Wise landscapesS outh African landscapers are internationally acknowledged as experienced professionals who are able to overcome a range of difficult climatic conditions in their bid to create beautiful landscapes.They also appreciate the challengeof landscaping in a country that is officially classified as having a semi-arid climate. Predictions from climate change experts suggest that even more trying 4 6 Basic principles of Water Wise landscaping Planning in hydro zonesconditions can be expected as world temperatures rise on account of global 8 Design Water Wise surfaceswarming. In South Africa, climate change is also expected to affect annual rainfall 10 Marvels of mulchdistribution patterns which will result in extended dry periods interspersed withexcessively wet periods. 12 Harvest rainwater With an ever-growing population and pressure on the availability of potablewater, Rand Water has joined forces with the South African Landscapers Institute 16 Efficient irrigation(SALI) to promote the concept of Water Wise landscaping. The likelihood of water demand outstripping supply to the Rand Water footprint 18 Become a water managerbetween 2013 and 2020 are well documented.The available supply of water in the 19 Rainfall facts and figuresVaal River System will only increase when the new Lesotho Highlands Water Projectis completed in approximately 2020. This means that everyone, including office 20 Create a wetlandparks, golf courses and housing estates, will have to become ever more proficient inmanaging water usage. 22 Wise up on water features Rand Water’s Water Wise Guide to Landscaping outlines the basic principles 23 Water Wise container gardeningunderlying the creation and maintenance of Water Wise landscapes. Most of theimages used to illustrate these basic principles are from projects submitted by SALI 24 Water Wise management of buildingsPrincipal Members for the 2011 Awards of Excellence. Since 2005, Rand Water hassponsored a Water Wise Trophy at this event, and the Water Wise winners are 28 The South African Landscapers Institutelauded for their efforts. We hope that the Water Wise ideas, concepts and advice in this publication will 30 SALI 2011 Shield for Excellence winnerbe of benefit to everyone who develops, manages or maintains a landscaped 31 SALI Awards of Excellenceenvironment around factories, mines, office blocks, hotels, casinos, golf courses orhousing estates. 32 SALI 2011 Trophy winnersLeslie Hoy – Manager, Environmental Management Services, Rand Water 34 Rand Water’s Water Wise Trophy winnerPaul Kirkby – Chairman, National Committee, SALI 36 SALI 2011 Gold Award winnersEditorial Team 40 SALI 2011 Silver Award winnersRand Water Editors: Leslie Hoy & Meagan DonnellyConsultant Editors: Kay Montgomery, Beverley Ballard-Tremeer, Warren Schmidt 42 The value of a professional landscaperDesign & Layout: Arthur McLellan, Caréna BüchnerProduction: Kay Montgomery Editorial Services, tel: 011 723 9000 45 Landscaping extravaganzaRand Water Customer Service Centre Hotline: 0860 10 10 60Website: www.randwater.co.za 46 Accredited SALI suppliersEmail: firstname.lastname@example.org 48 Principal Members of SALIThis publication is a joint venture between Rand Water and the South AfricanLandscapers Institute (SALI), 2011.Cover:Water Wise and eco-friendly landscaping beauty of the site, and resulted in the creation of accompanying water restrictions, thereby protectingDesigned and implemented by Marina Landscaping, habitats for a variety of wildlife. the property owner’s investment in the landscape.this garden at the High Constantia Estate in the The riverine area at High Constantia was No bare soil can be seen anywhere on theConstantia Valley in Cape Town was awarded the completely cleared of alien invasive plants.This Estate, as all pathways are covered in mulch and all2005 Rand Water Water Wise Trophy. vegetation had been absorbing large quantities of beds are fully planted.This reduces evaporation The five hectare site comprises 19 residential groundwater and reducing water flow in the stream. from the soil by up to 70%.The private open spacesunits clustered around 2,5 hectares of open space. This area was rehabilitated with indigenous stream of residents comprise informal natural landscapedMarina Landscapes followed the recommendations and wetland plants.The river has a 10m buffer zone areas to mimimise the use of ‘waterholic’ lawn given in the on either side, which provides habitat for plants and areas.To create a recreational area the meadow Environmental animals, creating a biodiversity corridor. field was planted with buffalo grass, a relatively low Scoping Report and Most plantings comprise local indigenous plants water usage Cape turf type. designed a landscape – a total of over 200 different indigenous plant The Estate is now a bird-watcher’s paradise, and to preserve species. Such plants are well adapted to local is home to many frog and insect species as well as biodiversity and conditions, and therefore need little if any extra small mammals.The Estate showcases the principles habitats.The water beyond that provided by the local rainfall. of Water Wise gardening, illustrating how a beautiful indigenous plantings Local indigenous plants are also more likely to landscape can be created that also conserves water, retain the natural survive in the event of a prolonged dry spell with and animal and plant biodiversity.
2 Rand Water’s Water Wise Guide to LandscapingLandscaping for the futureLandscaping is evolvingto deal with issues ofwater security, whichare fast becoming aworldwide concern,particularly in water-shortcountries like South AfricaT he amount of fresh water on earth ABOVE: Modern landscaping takes water neighbouring regions from 2013, when conservation into consideration. (Pic: Chelsea Flower Show. projected population growth and develop- is constant, which means that the Designer: Philip Nash) ment will exceed the available piped water fresh water available today is exactlythe same as it has been for thousands of supplied to the region. Only in about 2020,centuries. And yet in the last 100 years the The day is fast when the new Lesotho Highlands Waterearth’s population has increased dramatically. Project comes on stream, will more waterFrom 1,6 billion people in 1900 there are approaching when there become available to Gauteng.now 7 billion people on earth, and thisnumber is expected to reach 8 billion in will not be enough water Landscapes for the future2025.The present population of Africa is – or affordable water – Water resources and their future availability1 030 million; it is expected to double by2050. for lush waterholic underpin the very existence of the The increasing demand made on existing landscaping industry. Landscape architects,water supplies by ever-growing populations landscapes designers, contractors and maintenanceis of enormous concern to both governments specialists, need to design landscapes thatand water authorities throughout the Leslie Hoy, Rand Water suit the new reality of predicted waterworld.The strain on water supplies was shortages, and to plan the most water-internationally acknowledged at the 1992 evaporation. Climate change is also affecting efficient on-site irrigation.United Nations Conference on Environment rainfall, with ‘drier dry spells’ and ‘wetter wet In this groundbreaking brochure, a jointand Development (UNCED) in Rio de spells’ being predicted. And increasingly, venture between Rand Water’s EnvironmentalJaneiro.The United Nations deemed it South Africa’s limited water resources have Management Services and the South Africannecessary to establish an annual World to be shared amongst an expanding Landscaper’s Institute (SALI), the ideas,Water Day – March 22 – to highlight the population, a growing business sector, concepts and tips that will transformimportance of water conservation and agriculture and our unique ecosystems, the landscaping sites into Water Wise models ofwater quality. latter of which generates a large part of our progressive excellence are presented. In water-stressed South Africa, studies tourism industry. We also celebrate landscapers andalready indicate that, as the population South Africans have been urged to save landscaping projects which have installedgrows, our limited water resources could be water in the workplace and at home.The a variety of Water Wise initiatives.Thesefully exhausted within the next 20 years. likelihood of future water shortages is not projects have been recognised by RandA variety of programmes have been initiated a fantasy. Reports from the City of Cape Water and each year the best Water Wiseby both government and water authorities Town indicate demand will exceed supply landscape is awarded Rand Water’s Waterto manage water resources more efficiently in eight years, and the Department of Wise Trophy.This prestigeous Trophy isand reduce wasteful water usage. Water Affairs has predicted that water presented at the annual SALI Awards of shortages can be expected in Gauteng and Excellence.Demand for waterSouth Africa receives an average rainfall of495mm, less than half the world’s average of What is water stress?1050mm. Hence South Africa is categorised South Africa is classified as a ‘water-stressed’ country as we have less than 1 700m3 ofas a semi-arid country that is water water per person per year. Unless we begin to use our limited water supplies wisely,stressed (see box).There is also an uneven South Africa will move into the ‘water-scarce’ category of less than 1 000 m3 per persondistribution of rainfall across our country, per year by 2025.and our hot dry climate causes excessive “Water conservation is destined to be an inevitable part of everyday life” Leslie Hoy, Rand Water
Rand Water’s Water Wise Guide to Landscaping 3Water Wise landscapes Become a water steward Water conservation can serve as an integral part of corporate sustain-Rand Water has led the way in promoting the ability practices, or the ‘greening’ of a business. Many often think ofdevelopment of landscapes that conserve water ‘greening’ as a technique that focuses on energy savings, but it is important to not forget the importance of ‘savingR and Water, the main supplier of potable water to Gauteng and neighbouring regions, has promotedwater conservation for many decades.Following international trends, the Environ- launched numerous Water Wise initiatives and developed Water Wise demonstration gardens at the Delta Park Environmental Centre in Victory Park in Johannesburg and the Walter Sisulu National Botanical blue’. Not only is water a limited natural resource, but there is also a fundamental water-energy connection as the treatment and delivery of water requires a great deal of energy.mental Management Services of Rand Water Gardens in Roodepoort. Being an active water steward ishas become increasingly interested in A Rand Water Water Wise Trophy was one more way to enhance a company’squantifying the amount of potable water donated to the South African Landscapers image and improve employee prideused in landscapes. (Potable water is water Institute in 2000 and is awarded annually and motivation. Besides positive PR,from natural sources that has undergone to the landscape company that has an organisation will benefit with costcostly purification processes to render it safe designed the most Water Wise landscape savings, including lower maintenanceto drink. Delivered through a complex (see page 34).This award is an accolade and equipment replacement costs, insystem of pipes and reservoirs, it is often of recognition for the winning landscapers addition to reductions in water bills.referred to as municipal water). and is highly prestigious, as it guarantees A number of prestigious Interest in water efficient landscapes the future clients of these landscapers a organisations provide guidelines onbegan in the 1970s, when research in the team fully conversant with Water Wise how businesses can practice environ-semi-arid, south-western states of the USA landscaping principles. mental conservation in general,indicated that irrigation of landscapes in Landscaping professionals and plant including water conservation. Thesethese dry regions accounted for about 50% growers are now well aware of the need to include the American Audubonof total domestic water use. The severe create Water Wise landscapes that conserve Cooperative Sanctuary Programme,drought in these regions in 1977 resulted water. Rand Water researchers continue the International Organisation forin the imposition of water restrictions to keep the general public, as well as Standardisation and the South Africanwhich impacted negatively on landscapes. professionals, informed about water Heritage Environmental ManagementSubsequent research demonstrated that, conservation by means of magazine and Company. All give recognition forif a specifically designed low water usage newspaper articles, brochures, informative achievement of their objectives.landscape was installed (instead of high talks, and the Water Wise website. (Visit In every business or factory therewater usage European-inspired plantings), www.randwater.co.za and click on the Water are simple steps that can be taken toand irrigated with precision, landscape water Wise logo.) conserve water.These include fixingusage could be reduced by about 70%. Rand Water’s researchers have also leaks, installing low-flow showerheads, identified the water needs of a wide range installing high efficiency toilets,Rand Water and the of plants, and continue to be right up to installing Water Wise landscaping andWater Wise campaign date with the latest water saving techniques recycling processed water. However,During the drought of 1994/5, Rand Water and products.These findings are of major the best savings will occur if alaunched a Horticultural Forum as part of interest to South African landscapers, who business creates an overall watertheir campaign to highlight the importance are at the forefront of innovative design. management plan.of Water Wise gardens, landscapes and The following pages highlight research which The three best practices for allrecreational facilities in the Gauteng region. focuses on the many ways that the water organisations are:Shortly thereafter the Water Wise brand needs of an attractive landscape can be • Have a goal to save water.was launched. Since then, Rand Water have reduced to the absolute minimum. • Identify and implement water efficiency measures. • Monitor savings and progress. LEFT: Businesses can conserve water by installing an attractive Water Wise pavement planting rather than simply lawn as shown here at the entrance of the Waterfront Office Park in Cape Town. Landscapers: Greenacres Landscapes. (Pic: Courtesy of SALI) FAR LEFT: Launched in March, 2011, the Water Wise garden at the Walter Sisulu National Botanical Gardens includes water harvesting techniques, hydro zoning, indigenous low water plants and a variety of mulching techniques. It also proves that water wise gardens can be enormously attractive. “One of the most difficult things is not to change society, but to change yourself” - Nelson Mandela
4 Rand Water’s Water Wise Guide to Landscaping Eight rules for Water Wise design • Plan and design to conserve municipal water and harvest free rainwater.Basic principles • Remove declared alien invader plants – they over- consume water and destroy habitats. • Create practical turf areas of manageable sizes and shapes, and select appropriate grass types.of Water Wise • Zone the landscape into different hydro zones and group plants according to their water usage. Make the low water usage zone as large as possible.Thereafter, determinelandscaping how much and how often to water through the seasons. • Use soil amendments such as compost, manure and water retentive polymers. • Use mulches, especially in high and moderate watering zones. • Irrigate efficiently with properly designed systems, and bySite assessment and planning applying the right amount of water at the right time. • Maintain the landscape appropriately by mowing,are vital pruning and fertilising properly.W ater Wise landscaping is an approach to landscaping that focuses on water conservation.Climate-appropriate plant choice andefficient irrigation are key factors. Others A Water Wise landscape is simply one in which basic principles of water conservation have been applied right from the start – although any existing landscape can be altered to make it Water Wise.are grouping plants with similar water The best time to convert an existingrequirements together in different hydro landscape to one that is Water Wise iszones, watering just enough to meet plant when it needs a revamp. If buildingneeds, and installing non-water consuming alterations are to be carried out, this is alsoareas, such as paved or gravelled sections. a good time to reassess the landscaping.The use of local indigenous or other lowwater usage introduced plants is a priority. Planning and design Being Water Wise does not necessarily Planning involves identifying the client’simply only one particular landscape style. Planning to make the best use of site assets and preferences, intended uses and goals for theRather, it is a concept of water conservation limitations is important. At the Mount Grace Hotel in landscape.These goals are then combinedthat may be applied to landscapes of any Gauteng, sloping ground permits water to be harvested with the environmental features of thestyle, from formal to informal in layout, to in a dam. Landscaping: Servest Landscaping. property to create a map.This ‘synthesiscontemporary or traditional in appearance. (Pic: Courtesy of SALI) map’ is refined by applying both standard and Water Wise design principles to create A Water Wise landscape is cost efficient an attractive landscape. Planning to make the best use of site assets and limitations is important. Assets may include views, rocky outcrops, a boggy A retention pond slows down floodwater area suitable for wetland plantings, areas with sunlight or shade, as well as existing During construction of the Echo Edge apartment building in Port Elizabeth the vegetation vegetation. on an adjacent steep slope suffered damage.The area was re-vegetated, and berms and Design principles include scale, balance, swales were constructed to slow down and manage fast-flowing stormwater that would interest, harmony and continuity. Three otherwise have flowed unrestricted into the Baakens Valley Nature Reserve, carrying with additional design considerations that are it valuable topsoil, and causing serious soil erosion to the valley walls. Landscaping: important in Water Wise design are: Ulterior Design. • Dividing the area into different hydro zones. • Creating shaded areas to help preserve moisture in the soil. • Creating windbreaks to prevent wind drying out the soil. Implementing a plan may involve site grading, creating berms and swales to harvest rainwater, preparing and amending soil to make it more water-retentive, planning and installing an irrigation system, constructing no water usage hard landscaping surfaces, planting up high water usage, medium water Construction of berms and swales. After construction. (Pic: Courtesy of SALI) (Pic: Courtesy of SALI) usage and low water usage hydro zones, mulching and maintenance. “As both population and water demands increase, and existing water supplies correspondingly decrease, the cost of potable water will increase.” Leslie Hoy, Rand Water
6 Rand Water’s Water Wise Guide to LandscapingPlan different hydro zonesDifferent plants have different water needs so planand plant accordinglyT he key design principle of a Water Wise landscape is to group plants with similar water requirements inthe same area. A landscape can have fourhydro zones: A high water usage zone, small, and the high water usage zone even smaller. Also take into account the following: • Plan no or low water usage zones for windy exposed areas and the heat- No water usage zone Make this hydro zone as large as possible. It comprises mainly of hard landscaping surfaces such as paved or gravel areas and parking areas that need no water. However,a moderate water usage zone, a low water collecting hot areas adjacent to the north- established local indigenous trees andusage zone and a no water usage zone. or west-facing walls of buildings. shrubs, as well as many succulent speciesThis approach allows for small areas of high • Make use of areas where rainwater can be included in this zone.water and medium water usage plants, but temporarily collects for medium waterat the same time results in water savings of usage zones or a wetland area. Low water usage or ‘1 drop’ plantbetween 30% and 80%. • It is more water efficient to plant high zone water usage ‘3 drop’ plants in containers Make this hydro zone large.The plants forPlan different planting and group the containers together to this area are those that thrive mainly onzones create a focal point. the local rainfall. They tend to be localFor greatest water conservation most of the indigenous plants. Once established, theylandscape should be designed as low water Four zones only need a little, if any, watering. In summerusage and no water usage zones. Make Apply the four zones principle to conserve water only once every four weeks. In winterthe moderate water usage zones relatively water. water only once every eight weeks. Water Wise landscapes promote biodiversity Water Wise landscapes recognise the value of local indigenous plants that are naturally adapted to prevailing weather conditions and rainfall. And, quite logically, local indigenous plants provide a habitat for a wide variety of local wildlife. As ever-expanding cities destroy natural habitats and wetlands, many local plants and animals are becoming endangered, to the extent where extinction is a possibility.To highlight this new millennium threat, the United Nations declared 2010 the International Year of Biodiversity. Businesses can become 21st century ‘heroes’ by commissioning a landscape that conserves water and also provides a haven for wildlife. Practical advantages are a reduced water bill, little or no lawn mowing, and less fertilisation and maintenance. The predominantly indigenous plantings in the 43 hectare Veld Estate of the Woodlands Office Park is home to a wide variety of wildlife. Landscapers: Servest Landscapers. (Pic: Courtesy of SALI) “Don’t blow it – good planets are hard to find” Time Magazine headline, 2007
Rand Water’s Water Wise Guide to Landscaping 7 A well planned Water Wise landscape results in water savings of guide to plants between 30% and 80% Choose the correct plants for each hydro zone ‘1 Drop’ plants for low water usage zone: Once established, these plants do not need water, except during very hot dry spells. Local indigenous plants are an ideal choice. Only water in winter if they show signs of distress. Established local trees and shrubs, as well as most succulents, will not need any extra water. Some examples are: • Trees: Acacia spp., tree aloe, Buddleja spp., wild olive, karee, bush willows, Celtis africana, Dovyalis zeyheri, Erythrina lystistemon. • Shrubs: Abelia, carissa, confetti bush, euryops, felicia,FAR LEFT: A no water zone. Most cacti and lavender, rosemary, Plectranthus neochilus, philodendrum,succulents thrive on local rainfall and require no plumbago, Indian hawthorn, strelitzia, Cape honeysuckle. Arctotisextra irrigation. Shown here is The Succulent Garden • Perennials: Agapanthus, asparagus ferns, clivia, Capeat The University of Pretoria. Landscaping: Amaloba thatching reed, Dietes spp., gaura,Horticultural Services. (Pic: Courtesy of SALI) blue statice (Limonium perezzi), Tulbaghia violacea.CENTRE: A high water zone. For greatest water • Groundcovers: Arctotis, stalked bulbine, hen-and-chickens, erigeron, trailing gazania,conservation keep this zone as small as possible. Plectranthus spp., trailing osteospermum, Sutera spp., star jasmine, vygies.Planting colourful annuals and bulbs in containers is • Bulbs: Fan-leaved boophane (Boophane disticha), Crinum spp., Ornithogalum thyrsoides.highly water efficient. (Pic: Loren Shirley-Carr)LEFT: A medium water zone. Keep this zonerelatively small - shown here is a small rose garden ‘2 Drop’ plants for medium water usage zone:at the Westcliffe Hotel in Johannesburg. Landscaping:Servest Landscaping (Pic: Courtesy of SALI) Once established these plants do not need much waterABOVE: A low water zone.The pavement area of the during the rainy season, except during very hot drySunridge Shopping Centre in Port Elizabeth is planted spells. Water once a month during the dry season. Someup with colourful but low water usage indigenous examples are:plants. Landscaping: Ulterior Design. (Pic: Courtesy of SALI) • Trees: Silver birch, leopard tree, Juniperus spp., Platyclydus orientalis cvs., Melaleuca bracteata, deciduousModerate water usage or ‘2 drop’ oaks (Quercus spp.), Populus simonii.plant zone • Shrubs: Aucuba, buxus, coprosma, cordyline, cuphea,Keep this hydro zone relatively small. The Cycas revoluta, Duranta cvs., Freylinia tropica, gardenia,plants for this area are those that need more hisbiscus, box honeysuckle (Lonicera nitida), forest bellwater than that which is provided by the (Mackaya bella), mahonia, nandina, roses, Solanumrainfall in your area. Many popular exotic plants rantonnetii, Viburnum species.are ‘2 drop’ plants. In summer water once a • Perennials: Shasta daisy, diascia, dianthus, hellebores, Day lilyweek. In winter water once a month. Hemerocallis spp., kniphofia, New Zealand flax. • Groundcovers: Carex spp., Festuca spp., Liriope spp., mondo grass, lamb’s ear, snow-in-High water usage or ‘3 drop’ plant summer (Cerastium tomentosum).zoneKeep this hydro zone as small as possible, ‘3 Drop’ plants for high water usage zone:or even eliminate it altogether, as high waterusage plants need frequent watering Once established these plants need regular wateringthroughout the year. If included, it makes every 3 days in summer, and more often during hot drysense to position this zone where it is highly spells. Water at least once a week during the dry season.visible, such as a front entrance. Some examples are: Azaleas, camellias, tree ferns, fuchsias, The following types of plants all have Cape fuchsia, white arums (Zantedeschia aethiopica)high water needs: lawn, bog or wetland Canna hybrids, dahlias, acorus, Ajuga spp., creeping Jennyplants, exotic ‘3 drop’ plants, annuals and (Lysimachia spp.), Lamium spp., baby’s tears (Soleiroliabulbs. In summer water 2-3 times every soleirolii), all winter flowering bulbs and annuals. Fuchsiaweek. In winter reduce watering by halfand water 2-3 times every fortnight. “The frog does not drink up the pond in which it lives” Chinese Proverb
8 Rand Water’s Water Wise Guide to Landscaping What is hard landscaping? Hard landscaping refers to any non- plant surface area in a landscape whereDesign Water Wise alternatives to plant material are used. It includes outdoor terraces and patios, parking areas, paths and steps.Thesesurfaces areas can comprise concrete or brick, cobble or flagstone paving, sleepers and stepping stones set in pebbles, gravel or bark chips, according to their purpose.Instead of putting down lawn on flat landscape In a Water Wise landscape it is vital that solid paved areas make provisionsurfaces, install low water usage alternatives for rainwater runoff – see below.T he materials used to cover the ground surface of a landscape have great bearing on the potential waterconservation of a property.A low water usagesurfacePlant low-growing ‘1 drop’ ground covers.Evergreen ground covers are best as theylook good all year round. Large swathes ofjust a few plant species with contrasting ABOVE: A no water surface: paved surfaces andfoliage are particularly effective. Low water areas covered with gravel or pine bark nuggets atusage ground covers include dwarf Walter Sisulu Botanical Gardens. (Pic: Leslie Hoy) ABOVE LEFT: A no water surface: a surface comprisingagapanthus, stalked bulbine, dymondia, low growing succulents and aloes at the Woolworthstrailing gazania, trailing osteospermum and Plant natural grasslands. Make the area Distribution Centre in Gauteng requires no extrawild garlic (for sun); and Asystasia gangetica, a fashionable prairie-like natural veld grass irrigation. Landscaping: Servest Landscaping.Asparagus densiflorus, hen-and-chickens, area. Such grasses need only local rainfall (Pic: Courtesy of SALI)Drimiopsis maculata, variegated plectranthus to thrive. ABOVE RIGHT: A low water surface: evergreen lowand sutera (for shade). water usage ground covers make for an attractive and permeable surface area in the middle of the parking Plant ground-covering succulents.A no water usage A professional landscaper is well informed area at River Walk in Pretoria. Landscaping: Greenacres Landscapes. (Pic: Courtsy of SALI)surface about local low growing succulents that arePlant local Cynodon lawn varieties. Most perfectly adapted to local conditions and water conserving designs.The larger suchexotic lawn varieties are high water usage need no extra irrigation. Succulent surfaces surfaces are, the more water is conserved.plants.To conserve water and minimise cannot be used as recreation areas or walk Recent research indicates that such surfacesmaintenance reduce or eliminate lawn areas. ways as foot use will damage the succulents. actually may help to retain moisture in theSelect indigenous Cynodon varieties that are soil by keeping the soil cool.The moisturenaturally dormant in winter and thrive on Install hard landscaping. Such surface then becomes available for neighbouringlocal rainfall only. treatments are particularly important in plantings. Permeable surfaces are preferable Surfaces that are water-permeable are always preferable to impermeable paved areas. A permeable surface is one that allows rainwater to percolate through it into the soil beneath. Such water remains cleaner and less polluted than stormwater that has flowed over impermeable surfaces such as roads and pavements. Polluted water is detrimental for natural ecosystems LEFT: Permeable concrete pavers. (Pic: Leslie Hoy) and makes the provision of piped drinking water more expensive. CENTRE: Permeable flagstone and gravel. (Pic: Lukas Otto) Examples of permeable hard-scaping surfaces are: RIGHT: A permeable mulch pathway. (Pic: Courtesy of SALI) - Permeable concrete pavers.These are a good choice for under large trees, driveways and parking areas. Where impermeable paving is unavoidable, install it in such a way as - Gravel and small pebbles. to direct rainwater into adjacent planted areas.This can be achieved - Spaced flagstones with pebbles in the gaps. Use for pathways and by means of a slightly sloping surface that is barely detectable, or, in terraces. the case of a driveway, with judiciously positioned and very slightly - Spaced flagstones with a very low-growing Water Wise ground sloped berms. cover planted in the gaps. Where large areas are already paved, install infiltration basins - Pine bark nuggets or shredded bark for paths in informal natural planted with trees. Micro-organisms and root systems in the soil act or indigenous areas. as filters and clean stormwater as it travels down through the soil. “Plant up a landscape in autumn when establishment watering requirements are lower” – Leslie Hoy, Rand Water
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10 Rand Water’s Water Wise Guide to LandscapingMarvels of mulchCovering the soil with a layer ofmulch is an essential aspect ofWater Wise landscapingM ulching dramatically reduces water loss from the soil due to evaporation, so that less frequentwatering is required. Which mulch to chooseand the depth of the applied mulch dependson the landscape theme, availability ofvarious mulches and the local climate. • Mulched soils do not need digging, as A properly mulched micro-organisms and earthworms do allTypes of mulch the work. landscape can save • Partially decomposed compost makes• Organic mulches. These come from plant excellent organic mulch and is particularly between 50 to 70% water, and animal sources and are the best sort appropriate and cost effective for of mulch because, as they break down, businesses where the establishment of as the water in the soil they enrich the soil. Examples are compost, a compost heap made from kitchen and fruit pips, nut shells, bark nuggets, wood garden waste is viable. cannot evaporate so chips, cobs and autumn leaves. Organic mulches need to be topped up regularly. quickly• Inorganic mulches. These are substances or materials that do not break down and enrich the soil, but help keep moisture in the soil. Examples are gravel, pebbles, stone chips and pavers. As they can store heat they need to be used judiciously; they are most suitable in shady areas.• Living mulches. Ground covering plants serve the exact same purpose as other types of mulch, and may be preferable for aesthetic reasons. Low water usage ground covers are the most Water Wise choice.The benefits of mulch• Mulch reduces soil temperature, so less water is lost to evaporation.• It promotes good root growth by retaining moisture in the root zone.• It suppresses water-consuming weed growth by keeping out the light.• Mulch provides winter protection in cold climates, preventing frost damage to roots.• It reduces exposure to wind, which results in less moisture loss through evaporation.• It controls erosion by softening the impact of falling water and slowing it down so that it can soak into the soil before running off.Benefits of organicmulch• Organic mulch eventually breaks down and improves the quality and water- holding capacity of soil near the surface. “A 5cm layer of leaf litter reduces evaporation by 45-65% depending on the type of leaf”
Tips for organic mulch use - Organic mulches must at least be 5-8cm thick for normal soil and 8-12cm for a sandy soil. With clay soils 2-4cm is sufficient under normal conditions. - During dry or cold periods the level of mulch needs to be thicker than during wet periods to protect plant roots. - As organic mulches break down in the decay process, they need to be replenished. Compost decomposes in two to four months, whereas bark chips last about two years before being broken down. - In spring, after the last frost, it may be necessary to pull mulch back from emerging plants, especially small perennials. - If a particular mulch creates a nitrogen deficiency, correct by adding a solution of ammonium sulphate, dried blood or rock phosphate.ABOVE: Mulching is highly Leaf litter is ‘in’effective in retaining moisture inthe soil. Shown here is the Maintenance services often think they are doing theHoughton Golf Course entrance right thing by ruthlessly clearing beds and bordersin Johannesburg. Landscaping: of fallen plant debris for the sake of neatness.ThisHorticare. (Pic: Coutesy of SALI) practice is outdated in landscapes of the future asBELOW : An inorganic rock bare soil inevitably loses its moisture content. A 5cmmulch has been utilised at the layer of leaf litter reduces evaporation by 45-65%Dept of Health Offices in the depending on the type of leaf; pine is the best.North West. Landscaping:Amaloba Horticultural Services.(Pic: Courtesy of SALI)BELOW LEFT: A living mulch isjust as effective as inorganic andorganic mulches. Choosing lowwater usage groundcovers withsoil retentive roots is the bestchoice for sloping ground.Landscaping: ServestLandscapers. (Pic: Courtesy of SALI) Pic: Leslie Hoy “Nearly 91% of South Africa falls within the United Nations’ definition of affected drylands, which are extraordinarily dry areas where the rainfall is low and the evaporation is high”
12 Rand Water’s Water Wise Guide to Landscaping Water harvesting winnerHarvest rainwaterMake maximum use of rainwaterto irrigate a landscapeW ater is a precious resource that should not be wasted and certainly not thrown away. And yet, by not making the most of free rainwater, it is, in effect, being thrown away. Rather than letting this free water runoff a property, use it to irrigate the landscape by directing the water to where it isneeded, such as a high water usage zone, a wetland or a pond. Alternatively, it can be Large and sloping hard-landscaped areas designedstored in water tanks for later use. Collecting rainwater for use in a landscape is to harvest water. Landscaping: Life Landscapes.known as rain harvesting. (Pic: Courtesy of SALI)Harvest rainwater from the roof At the Pivot Hotel at Montecasino in Sandton,Collecting rainwater from the roof is the most efficient means of harvesting water. Life Landscaping utilised the slightly slopingEvery 1m2 of roof generates one litre of water from 1mm of rainfall. Put differently, paved areas to direct stormwater runoff into ain a region with South Africa’s average annual rainfall (464mm per annum), 464 litres catchment system, and from there into a dam.(0,46 kilolitres) of free water can be harvested per year per 1m2 of roof. Water from the dam is used to irrigate the To find out how much rainwater in litres can be harvested from a particular roof small high water usage zone which comprisesper year multiply the area of the roof in m2 (or the ground area of the building) by the plantings with retaining walls.amount of rainfall your area receives per year in mm. Allow for 15% wastage. Deduct The retaining walls hold water in the beds,this amount from your annual water usage to see how much less water you would be keeping the soil moist for longer. Clean,paying for annually. unpolluted rainwater from the roof, is directed to storage tanks in the basement area and from there it flows into a neighbouring stream. Slightly sloping paving directs runoff. By using water wisely up to 50% of landscape irrigation water can be savedConstruct berms and swalesSwales (shallow depressions) and berms (slight ridges that are higher than the adjacentsurface area) that are carefully positioned in a landscape, harvest water by keepingrainwater from a heavy downpour from being lost to runoff.They are particularlybeneficial on a sloping site. A berm at the lower edge of a slightly sloping lawn area will harvest water for thelawn.Very slight concrete berms on a solid surface driveway can direct runoff into anadjacent high or medium water usage zone. And a swale that collects runoff rainwatercan be the basis of a wetland or pond area (see page 20).Terrace slopesThe rainwater that falls on slopes is all too easily lost to runoff. In the process it Stormwater runoff is directed into a dam which provideserodes the soil, taking off the fertile top layer.Terracing sloping ground to create level free water for irrigation. Landscaping: Life Landscapes.areas of soil is a Water Wise practice. By constructing terraces rainwater runoff is (Pic: Courtesy of SALI)slowed down, permitting more water to soak into the soil.This makes terraced areasideal for plantings. In addition, a multi-level terrace makes an attractive landscapefeature. To collect rainwater for treesDirect rainwater into ponds and dams and large shrubs, contour theRainwater from gutters and hard surfaces can be directed into decorative ponds,storage dams or water tanks. Such water features are set to become a characteristic landscape so water collectsof future landscapes. On a practical level, the water in dams can be used for irrigatingthe landscape. under the drip line “Conservation is about managing our natural resources, from the largest watershed to the smallest ecosystem” Essex Regional Conservation Authority, UK.
14 Rand Water’s Water Wise Guide to Landscaping ADVERTORIALLandscaping going even greenerWith the ever increasingpressures on naturalresources and the sureindication that demandfor water in South Africawill outstrip supply by2025, the landscapingindustry is beingtransformed from aprimarily aesthetic serviceto one that impacts thevery sustenance of lifeon our planet.T he landscaping industry can lead the way in educating both corporates and homeowners on the importantrole of rainwater harvesting to secure thefuture of both the planet and the landscaping Design green spaces between hard surfaces (patios, walkways and parking lots) and building edges. (Pic: Greenacres, SALI)industry. Substituting rainwater for all waterapplications excluding drinking water, couldresult in a potable water saving of around50% of all domestic water consumption, andmore than 80% of consumption in corporateand public buildings, thus relieving theimmense stresses placed on municipal watersupplies (not to mention the accompanyingwater bills!). It is no wonder that rainwater harvesting,in conjunction with water wise, sustainablelandscapes and permeable paving is amongstthe top 10 international landscaping trends. Principles of water wise landscaping1. Plan and design for water conservation.2. Green retaining walls by building small out-pockets and planters on the sides to absorb water and reduce run-off.3. Reduce impervious surfaces by, for example, replacing solid driveways with porous alternatives. harvesting tanks in the landscape design.4. Interplant flagstone walkways with With the variety of sizes, stylish options creeping groundcovers, such as thyme, and fashionable colours available, smaller which will help to slow stormwater flow sized tanks can be unobtrusively and create a more aesthetic space. positioned under decks, alongside5. Design green spaces between hard walkways or vertically against a wall. surfaces (patios, walkways and parking Alternatively, consider underground lots) and building edges. water storage tanks. JoJo Tanks have6. Include the installation of JoJo rainwater a wide range to suit this application.
16 Rand Water’s Water Wise Guide to LandscapingEfficient irrigationA properly designed andmaintained irrigation systemboth conserves water andpromotes a thriving landscapeT he choice of an irrigation system and how it is implemented in different hydro zones has a great impact onthe efficiency of water use on any site. in a landscape to have different watering schedules. Automatic systems offer the benefit of programmable controllers. However the danger lies in ‘setting and forgetting’. For ABOVE: Drip irrigation is particularly good for mulched areas because it does not wash away the mulch, as can be the case with a sprinkler system. (Pic: Courtesy of Netafin)Automatic systems maximum water efficiency the timing of the account – depending on received rainfallThe most efficient irrigation system – and irrigation needs to change seasonally, as the it is quite feasible to switch off the irrigationcertainly the least time-consuming – is an quantity of water required by plants varies system for a few days. Linking a rain sensorirrigation system with an automatic controller from summer to winter.To conserve water, into the automatic system ensures thatthat allows for the different hydro zones the rainy season needs to be taken into irrigation will be halted automatically during rainy periods (see box). Drip versus sprinklers From a Water Wise perspective, drip irrigation is preferable to sprinklers and lawn pop up systems. A drip irrigation system emits 2-15 litres of water per hour, whereas a sprinkler system emits 2-7 litres per minute. Research in the dry south-western states of America has shown that drip irrigation has a high level of water efficiency. Water drips directly into the soil, so there is less waste of water compared to sprinkler systems that spray water above the soil, where droplets are often blown away by the wind, or evaporate. Drip irrigation is particularly good for mulched areas becauseABOVE: A drip irrigation system emits water directly into the soil so that there is less water lost to wind or to it does not wash away the mulch.evaporation. (Pic: Lukas Otto) Drip irrigation is ideal for large shrubberies, as there is no interference from foliage and Install a rain sensor therefore no dry spots. Plants that are vulnerable to fungal attack, such as roses, An easy way to prevent overwatering is to install benefit from this form of irrigation as the rain sensor to override the automatic watering foliage does not get wet during irrigation. system during rainy weather. A rain sensor simply Awkwardly shaped and narrow areas, where senses rainfall. Once a designated amount of conventional sprinklers waste water by over- water has been detected, it shuts down any spraying, will also benefit from drip irrigation. regularly scheduled irrigation and makes sure that you do not have a public relations disaster on a References rainy day. - Landscape Irrigation Association of South Africa (LIASA) on tel: 021-558-4989; Email: email@example.com; website: www.liasa.co.za - The Drip Guidelines Manual on http://www.amwua.org/publications/guidelines-for- Pic: Lukas Otto landscape-drip.html or http://amwua.org/pdfs/drip_irrigation_guide.pdf “Overwatering is not practical or economical. It runs up electricity bills, fosters soil compaction, and encourages weeds and diseases” National Parks and Recreation Association, USA
Rand Water’s Water Wise Guide to Landscaping 17 ABOVE: Narrow areas, where conventional sprinklers waste water by overspraying, benefit from drip irrigation. (Pic: Courtesy of Netafin) LEFT: Slopes need to be irrigated more slowly than flat surfaces. Landscaping: GvH Landscapes. (Pic: Courtesy of SALI)Code of StandardsThe Landscape Irrigation Association of SouthAfrica (LIASA) has a Code of StandardsManual for the design, installation and management of irrigationsystems. The aim is to assist contractors, dealers, specifiers,developers, architects and building managers in the correctapplication, installation and maintenance of landscape irrigationsystems for South African conditions. Now in its 3rd edition, the Manual was compiled by a teamof local irrigation experts to ensure an efficient and troublefree system. Included in the manual are tables which offerguidelines for soil infiltration rates and average irrigationrequirements.There is also information about how to take intoaccount the prevailing climatic conditions. Formulas forcalculating the precipitation rates of all sprayheads (microsprays and cone heads), rotating sprinklers (mini to large) andemitters (bubblers and drippers) are included, as well aspotable water flow testing methods and equipment. Any LIA professional has access to this Manual and canadvise building managers on any excessive use of water relativeto the area under irrigation. It wastes water to over-irrigateplants that grow well with minimum water. In fact, many such plants will die if overwatered “The crisis of our diminishing water resources is just as severe – if less obviously immediate – as any wartime crisis we have ever faced” Jim Wright, US Representative at Water Conference
18 Rand Water’s Water Wise Guide to LandscapingBecome a water managerProper irrigation practices can lead towater savings between 30% and 80%T o become a water manager requires the assistance of a professional team of irrigation andlandscaping consultants who can set in placesystems that allow for monitoring the water • Water less frequently but more deeply. This encourages deep root growth that sustains the plant during dry periods. Frequent watering causes a plant to develop roots in the first few centimetres ABOVE: If water from a sprinkler system puddles instead of sinking into the soil, change the programme to deliver the required amount of water in two sessions rather than one session. (Pic: Schmidt)usage in the various hydro zones on a of soil only, so in dry periods they cannotproperty. A well planned system will reduce use water deeper down in the soil profile.water usage and save time and money. This is particularly true of lawns. between 10h00 and 14h00 when For example, irrigation specialists take • Water-train trees and shrubs. By gradually evaporation rates are high. In winter,into account the following: changing from frequent shallow watering morning irrigation is best.• Turf areas are irrigated differently from to less frequent but deeper watering • Adjust the irrigation programme shrub borders. schedule, permanent plants can be according to the season. Plants need less• South and east exposures need less ‘trained’ to need less water. water during the cool winter season than frequent watering than north and west • Water in the early morning or late during the hot summer months. exposures. afternoon to reduce water loss to • If the sky is cloudy, irrigation can be• Slopes need to be irrigated more slowly evaporation. In the hot summer months reduced by as much as 50%. than flat surfaces. from October to February, avoid watering • Avoid irrigating during windy weather as• The need to use a number of emitters high winds blow away water delivered by around the drip line of trees, where the sprinklers and prevent proper coverage. roots are, rather than just one next to the • Turn off the system if rain is irrigating the trunk. landscape sufficiently. • If water from a sprinkler system puddlesBest irrigation practices instead of sinking into the soil, change theMaximum water conservation can be programme to deliver the requiredachieved by applying the following: amount of water in two sessions rather• Set automatic systems correctly and than one session. adjust them as conditions change.• Water only as frequently as your plants ABOVE: Constructing terraces to hold rainwater Best maintenance prevents soil erosion and conserves the water for need it.The different hydro zones have terrace plantings as demonstrated at Maropeng in practices different water requirements and require the Cradle of Humankind in Gauteng. Landscaping: Once an irrigation system is installed it different watering schedules. Servest Landscaping. (Pic: Courtesy of SALI) needs to be checked at least twice a year to make sure it is performing well. Particularly in the case of sprinkler heads, plant growth over time may call for adjustments to the system. • Check it for overall coverage. If planted up areas are not being comprehensively irrigated, adjust the system.This may mean replacing heads, adding more heads, or changing heads to do a more efficient job. • With the system on, observe places that are receiving water where it is not needed. Overlaps onto paved areas may result in considerable water waste. Overwatering trees and shrubs may lead to diseases. • Check all water connections in the irrigation system at least twice a year for leaks. During hot Highveld summers irrigate in the early morning or late • Replace all old worn washers. afternoon to reduce water loss to evaporation. Shown here is the Parys • Monitor sprinkler heads for any Golf and Country Estate. Maintenance: Evergreen Turf. (Pic: Courtesy of SALI) misalignment, and adjust the sprinkler heads as is necessary. “Water conservation is something we all should practice. Its too precious a resource to waste” - American Water Works Association