Conserving the Water Factories of the Western Cape
By Dr Ernst Barnard
The Western Cape is critical to any conservation effort in South Africa. It is not only one of the most ecologically complex and biodiverse areas in the world (due to the fact that it is home to more than 70% of one of the world’s six Floristic Kingdoms), but it is one of the primary water catchment areas for South Africa.
CapeNature, a public entity of the Western Cape Government and mandated with the conservation of biodiversity in the region, manages most of the mountain catchments and reserves that supply ecosystem services to its citizens, and the work that happens here has a direct bearing on the quality of life of millions of people in the province.
Healthy and functioning ecological infrastructure, that is, our rivers, streams, wetlands and seeps, in water catchment areas, and acting like “water-holding” and “water-producing” devices, provides clean, safe water to rivers, dams and ultimately to the end consumer. This paper demonstrates how the integrated management of three ecological processes, namely alien and invasive species, fire and freshwater, can be applied very successfully to conserve and, in many cases, restore these “water factories”.
The Western Cape holds 57% of the strategic water resources in the country, and 90% of the water catchment areas in the Western Cape are managed by CapeNature. These are typically the mountain catchments contained in a number of CapeNature nature reserves across the Western Cape, such as the Cederberg, the Boland and the Outeniqua Mountains.
Before delving into the actual management and restoration of these “water factories”, it’s important to highlight a number of threats to this important natural resource and ecological infrastructure, as well as some case studies of how CapeNature aims to protect and restore these natural water factories in the Western Cape. It goes without saying that without water, the Western Cape and its people, and indeed the whole world, would be a much poorer place. To begin, start by looking at a typical mountain catchment in the Western Cape; primarily covered in our famous fynbos which as a rule, does not really contain any trees. Normal run-off and water yield from a typical fynbos mountain catchment is maximised by the fact that a natural and healthy run-off process is maintained.
When trees are added, the situation changes quite dramatically, starting with the fact that on average, a mature tree, say a pine tree, consumes approximately 40-50 litres of water per tree per day. In 1995, Dye, Olbrich and Everson established that the greatest impact on water yield from a healthy mountain catchment area occurs when seasonally dormant vegetation, such as fynbos, is replaced by evergreen plants, such as invasive pine trees.
Thus, where grasslands or shrublands (like fynbos) are invaded by alien trees, the overall water use by the vegetation increases, leaving less water for the streams, and consequently for the end- user. Furthermore, in 1987, Van Wyk showed that infestation by invasive trees can result in a 55% reduction in streamflow (from 600 to 270 mm) in fynbos catchments, after 23 years of infestation with pines. This technically means that the water yield or run-off process has been significantly affected.
Alien and invasive species
The first ecological process in our mountain catchment areas is alien and invasive species. The current estimate is that invasive aliens cover approximately 10 million hectares in South Africa, and use approximately 3.3 billion cubic metres of water in excess of that used by native vegetation every year (that is almost 7% of the runoff of the country). These estimates indicate that the reduction in water yield is already significant and definitely large enough to warrant intervention. The logical conclusion is that these water losses will increase as alien plants invade the remaining, uninvaded areas. It is therefore in the interests of healthy catchments and the people of a region that immediate and decisive action is taken to protect the sustainability of water yield from South African catchments.
The second important ecological process in our catchments is fire. Because fynbos in the Western Cape region is a fire-driven ecosystem, fire remains a very important and necessary process. Fynbos requires fire to survive and to rejuvenate itself and without fire, fynbos dies. Therefore, any given fynbos fire is not necessarily bad news; it can be very good news. However, every year unwanted and uncontrolled veld and forest fires devastate our landscapes, affecting natural ecosystem functions, endangering life and ruining property. With the Western Cape being one of the worst affected areas in South Africa, it is necessary to pay special attention to fire management within the mountain catchments of the Western Cape.
CapeNature has been mapping fires in the fynbos for many years and over the past 14 years the region experienced 1 139 veldfires, on an estimated 1.2 million hectares of fynbos. Even though fynbos requires fire, the optimum frequency of fire needed is in intervals of approximately 10–15 years. Add to that the increased fuel load from invasive alien plants, and the result is that fires in the region are burning too hot and too frequently and are impacting on the production process of fynbos, hampering the ecology of the catchment areas for optimum water production. In an attempt to quantify ecological damage to fynbos by too-frequent fires, an ecological study was done by CapeNature’s scientists in the Boland area in 2009, following the Western Cape fires of December 2005. Using specific kinds of Protea species (re-seeders) as indicators, the aim was to establish the impact of the fire on biodiversity.
Using the established rule and threshold that 50% of the individual Protea plants in a population should have flowered at least three times before the next fire, the key finding in 2009 was that there did indeed seem to be a negative impact on biodiversity in the affected area of six-year-old veld. This was due to the fact that the Protea indicator species had insufficient time to flower and produce seeds. At least 80% of the Protea indicator species had not produced flowers at the time of the 2009 fire, which means that the plants could not form seed to produce the next generation. Some of these species need at least 12-19 years before 50% of the plants have flowered at least once.
In the big January 2013 fires (merely four years later), a large portion of the same study area was burnt, which meant that plants of the indicator species which had remained, definitely did not have enough time to flower, and that biodiversity was more than likely negatively affected. From a conservation point of view, this is extremely worrying.
The third ecological process is freshwater ecosystems. Due to the semi-arid nature of the South African and Western Cape Province landscape, conservation of freshwater ecosystems has become more and more important. The Western Cape is fortunate to still have some near-pristine mountain streams and upper foothill rivers, many of them found in CapeNature Nature Reserves and mountain catchments. The wetlands found in these mountain catchments are generally also found to be in good condition.
However, too many of the lower lying ecosystems such as rivers and wetlands in the rural and mostly agricultural landscape have been altered to a completely degraded state, often resulting in impoverished water quantity and quality. When freshwater ecosystems reach this degraded state, they also lose their ability to act as so-called “ecosystem services”, that is to, for example, supply fresh water during dry periods or to mitigate against serious ecological damage during severe flooding events.
Looking at the state of our Western Cape freshwater ecosystems, and according to the CapeNature State of Biodiversity Report of 2012, 45% of the province’s rivers and 71% of our wetlands in the Western Cape are threatened (either Critically Endangered, Endangered or Vulnerable), compared to 51% and 65%, respectively, at the national level. Lowland river ecosystem types and floodplain wetlands are the most threatened river and wetland ecosystem types. This is particularly worrying, as they are also the least protected of the river and wetland ecosystem types.
In order to assist planning for freshwater conservation, Freshwater Ecosystem Priority Areas were identified, and it was established that all the indigenous fish could for example be protected if we were able to protect a mere 17% of rivers in the Western Cape.
CapeNature takes the management and restoration of our mountain catchment areas and freshwater ecosystems very seriously and the following case studies of the ways we go about it will hopefully illustrate that we aim to make a difference.
Case Study 1: Duivenhoks
Since 2009/10 the Duivenhoks (near Heidelberg) and Goukou (near Riversdal) Wetland Rehabilitation Projects in the Hessequa Municipality of the Western Cape have been rated as the best among various wetland rehabilitation projects across the country. These two wetland ecosystems, both Palmiet-dominated, peatland systems, are rehabilitated as they are considered of high value for both biodiversity and water supply to nearby towns and farms. These two systems have been impacted on mainly by ill-advised agricultural practices in the past. Many farmers have, for example, dug irrigation trenches in the wetlands or drained them for cultivation. In many cases, crops were cultivated too close to wetlands or even within their boundaries.
The project started in the Goukou wetland system where a gabion structure was constructed in the middle of a very sensitive and inaccessible wetland, and which has been restored to the point where it has withstood some serious flood events (500mm in two days) proving that the design and workmanship were up to task. With the completion of this structure, a new structure was started on the Duivenhoks system, too. This is a much bigger structure also made of gabions and with difficult access. Both these projects are deemed successes and the wetlands are functioning and relatively healthy again.
Case study 2: Berg River Improvement Plan
The Berg River is a vital source of water in the Western Cape, not only for farmers, but also for industrial development, human consumption and recreation. In January 2013, the Western Cape Government approved a plan to spend R16 million, over the following three years, on improving the quality of water in the Berg River. The project is a joint effort between the Western Cape Government, the Department of Water Affairs, CapeNature and the various municipalities in the area.
This is a multi-faceted project, which is aimed at:
- Monitoring water quality: Water is being monitored for the presence of heavy metals, pesticides, pesticide residues, nutrients, as well as E. coli, at 20 sites identified as critical in the river and estuary areas.
- Upgrading wastewater treatment works: Both the Franschhoek and Wemmershoek wastewater works are being upgraded, in partnership with the relevant municipalities.
- Upgrading the informal settlements alongside the Berg River: looking at how a community can maintain a healthy state, regulate its own waste and heal its own water.
- Introducing sustainable practices and the efficient use of water in agriculture: We are working with farmers and golf estates in the riparian zone, on the best and most efficient use of water.
- Rehabilitation and bioremediation: CapeNature and Working for Water have undertaken alien vegetation clearing in Hermon, Drakenstein, and near Voëlvlei Dam, with corresponding planting and bioremediation in these areas.
Also, economies of water: Looking at how much water is used by the region’s economy, where and how it is used, analysing consumption in terms of economic productivity, and designing and implementing interventions to alleviate constraints. This is certainly not a short-term plan. The Berg River Improvement Plan is a joint effort from a number of different agencies who are working together towards a common goal—that the Berg River will continue to be a valuable and protected source of water into the future.
Case study 3: Job creation through conservation
Unemployment is a key issue in South Africa; and CapeNature and other conservation authorities realised that conservation provides opportunities for employment, particularly in poorer communities.
Programmes like the Expanded Public Works Programme, including Working for Water and Working for Wetlands, have provided jobs that play an important part in conserving our natural resources. The people employed in these programmes have been of enormous value in clearing alien vegetation, building firebreaks and infrastructure, as well as assisting during disaster situations, for example oil spills and floods.
Figure 8 depicts results obtained by CapeNature over the last few financial years including the number of jobs and full-time equivalents created.
CapeNature managed to make great strides in the past five years with the help of the Working for Water programme in terms of the management of invasive alien plants within protected areas. This is perfectly aligned with the Government’s attempt to create jobs and alleviate poverty, and has made a difference in many people’s lives.
Figure 9 illustrates how the different “Working for…” projects are deployed across the Western Cape region. The backdrop to these projects is the so-called “poverty layer” based on the Western Cape demographic statistics and, more
specifically, the unemployment per ward. With this approach, it is at least possible to make sure that some of the effort and money allocated towards job creation and poverty alleviation is spent in areas where it is most needed.
Looking at the amounts spent in the landscape, these efforts are making a significant difference in people’s lives.
Case study 4: Integrated fire management
Integrated fire management is the development and implementation of mitigation measures, standards and prescriptions based on comprehensive risk assessment, and aimed at reducing the negative impacts of veld and forest fires on social, economic and environmental assets. It is an adaptive process of continual improvement, involving record-keeping, monitoring, measurement
and modification. Integrated fire management also implies co- operation and coordination between all role players in the fire prone environment.
Partnerships between Provincial Disaster Management Fire Brigade Services, District Municipalities, fire contractors, Volunteer Fire Services and a number of Fire Protection Agencies, create a distinct effort for cooperation, rapid response and suppression. Integrated awareness initiatives and monitoring have proven to be successful during the last fire season (2013/14) with less hectares burnt; in fact, only one tenth of the area burnt during the previous season, even though there were the same number of fires.
The Winelands District Municipality is leading the way with a joint Integrated Fire Management Plan along with CapeNature to ensure better veldfire management within the Boland Area. This is an area which has been identified as a high risk area for ecological damage due to too frequent fires.
Case study 5: The Rondegat Rehabilitation Project
The Rondegat rehabilitation project demonstrates yet another way and angle of ecological restoration of ecosystems that have been affected by alien and invasive species. A 4.5km stretch of the Rondegat river in the Cederberg Nature Reserve managed by CapeNature has been cleaned of invasive small-mouth bass in order that this part of the river can be re-colonised by indigenous fish such as rock catlets, redfin minnows and Clanwilliam yellowfish. This project is deemed a big success and the latest monitoring results by independent scientific consultants have shown a return of this part of the river to a near-pristine stage, and colonised with all three species of indigenous fish expected to come back.
A healthy ecological system is healthy and free from “distress syndrome” if it is stable and sustainable – that is, if it is active and maintains its organisation and autonomy over time and is resilient to stress.
These case studies confirm CapeNature and the Western Cape Government’s dedication to the integrated management and restoration, where required, of the province’s mountain catchments and other ecological infrastructure in order that the people of the Western Cape can benefit from:
• more, cleaner and safer water to the end user,
• improved and sustainable farming practices,
• reduced erosion of ecosystems and reduced risk of disasters,
• better adaptation to climate change, and • the conservation and sustainability of the biodiversity of the region.
Source: The Sustainable Water Resource Handbook Volume 5
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