Watershed Management

Watershed Management

Watershed Management

Watershed Management

Catchment management is the applied management of a catchment area aimed at the sustainable delivery of its resources.

To achieve this, plans, programmes and projects need to be implemented to sustain and enhance catchment functions that affect the plant, animal, and human communities within a watershed boundary.

Features of a catchment that agencies seek to manage include water supply, water quality, drainage, storm water runoff, water rights, and the overall planning and utilisation of resources. Landowners, land use agencies, storm water management experts, environmental specialists, water use surveyors and communities all play an integral part in the management of a catchment.But planning together is vital across the landscape - including fire management, vegetation management and catchment management.

Steps in Catchment Planning and Implementation:

- Build partnerships

- Characterise the catchment

- Finalise goals and identify solutions

- Design and implement programmes

- Implement the catchment plan

- Measure progress and make adjustments

Integrated catchment management is a subsection of environmental management that approaches sustainable resource management from a catchment perspective. This is in contrast to a piecemeal approach that artificially separates land management from water management.Integrated catchment management recognises the existence of ecosystems and their role in supporting flora and fauna, providing services to human societies and regulating the human environment. Integrated catchment management seeks to take into account complex relationships within those ecosystems: between flora and fauna, between geology and hydrology, between soils and the biosphere, and between the biosphere and the atmosphere.

Integrated catchment management recognises the cyclical nature of processes within an ecosystem, and values scientific and technical information for understanding and analysing the natural world.

Fire Management

Fynbos is a fire-driven biome, fire being necessary to cycle nutrients and rejuvenate the vegetation. Fire, therefore, will happen, whether it is man induced or as a result of natural incendiaries such as lightning. In fynbos and grassland catchments, it is imperative to manage fire not only for the renewal of the vegetation but also for the management of runoff. Climate change has affected fire behaviour in yet to be researched and understood ways, and fires have burnt more frequently over larger areas during the last 10 years than in the previous 30.

In the Overberg district of the Western Cape, this has resulted in not only tragic loss of life and infrastructure, but also loss of livelihoods, displacing hundreds of rural flower pickers and their families into urban squalor. Wildfires have contributed significantly to the migration of people from the rural areas into urban residential areas with the accompanying social ills.

Too frequent fires has also resulted in the loss of biodiversity through fynbos vegetation that has not yet produced seed. In the case of most Proteas, plants will only flower and set seed after a number of years, depending on species, soil depth and aspect and rainfall. If these plants are burnt before at least 50% have flowered three times or more, insufficient seed is available to replace the adults. In some areas in the fynbos mountains of the Western Cape, large areas have been burnt before the plants could flower and set seed, leading to decreased biodiversity of species.

Climate change, the increase in temperatures coupled with increased CO2 levels, will promote the growth of certain species in the fynbos biome. A shift in rainfall toward spring and summer rains will further promote understory growth of grasses and sedges. As a result, fires seem to be sustained later into winter and are hotter, being driven by the strong winds of the Western Cape. This creates difficult and dangerous situations.

And yet the solution is so easy: strategic fire management as part of catchment management.

Obviously the cost of implementing such strategies is a major factor, but more than this is the barrier of coordinated public-private sector effort. All the ingredients are there to face these challenges: dynamic municipalities and fire services, the Working For programmes and private will.

Rory Allardice Environmental is proficient in dealing with all sectors and planning and facilitating strategic fire breaks and block burns in catchment areas.

- Fire breaks

- Block burns

- Vegetation Management

The first active vegetation management activity other than fire management that comes to mind is that of invasive alien plant infestation management. However, flower picking must also be managed to ensure the continuation and promotion of useable species for the industry.

The effects of higher CO2 are well known in the tunnel farming industry where levels of 1000 ppmv are achieved to increase and speed up production. Our present atmospheric levels are around 360 ppmv, having increased from about 330 ppmv over the last 50 years or so. That's pretty insignificant considering that CO2 is the primary plant food and nothing can survive without it, and that .0001% of carbon is present in the atmosphere. The rest is trapped in the earth, rocks, dead and living organisms.

We do not yet know the effects of higher CO2 levels on the fynbos in general, but we can hypothesize by using the research available on CO2 effects on plant families. C4 plants, mainly grasses, out compete C3 plants at higher temperatures, and therefore may have a larger impact on fynbos going into climate change.

Alien Infestation Management

Alien plant infestation threatens the natural health of fynbos by out-competing and displacing indigenous species, and by producing higher temperatures when they burn. The burning cycle for most alien species is shorter than that for fynbos, leading to more frequent fires and loss of fynbos species. Alien plants usually require more water to survive and have longer tap roots that indigenous species utilising ground water, thereby affecting seeps, sponges and fountains. Alien vegetation is considered the greatest threat to fynbos diversity by some specialists.

Climate change with accompanying higher carbon dioxide levels seems to have stimulated the growth of some alien acacia species, exacerbating the problem.Alien plant control requires fine-tuned planning in conjunction with agricultural activities and fire management. In certain situations it is advantageous to the landowner to manage the alien vegetation as a woodlot, deriving benefit through firewood or biomass used to fuel energy plants. It is critical where these woodlots are situated in catchments so as not to affect biodiversity and water production. This may well be the case in a municipal commonage where the community is reliant on the woodlot for building material and primary energy to heat and cook with.

A fire through the woodlot would devastate the community. A number of alien species, for example the Australian Acacias, are stimulated by fire and require immediate follow-up after a fire. Fire may be a good initial clearing tool in old fynbos but may generate an exponential increase in the alien vegetation cover unless follow-up is part of the plan.Agricultural activities in the most part promote alien spread. Animals hoof action and spread of dung carry alien seed into previously clean areas, and if these areas are of limited financial value to the landowner, he cannot spend money clearing and maintaining them. Catchments are generally poor agricultural areas and therefore have been neglected as far as alien vegetation management is concerned. Generally, weeds (aliens included), inhabit disturbed areas. Areas that have seen mechanical disturbance such as quarries, roads, and water works are usually infested with alien plant species and act as seed banks for further spread in catchments. These areas must be carefully managed to ensure that this does not happen.


Water is probably the most important product supplied by a catchment and people will always be concerned about the quality of that water. Pollution is therefore a major factor.

Pollution can be point source or non-point source and it's important to identify and apply reduction management for both. The use of certain herbicides in wetlands is inadvisable because of their accumulative effect and seepage into the ground water consumed by people and animals away from the wetland.

Spray drift from areas outside of the catchment may also contribute to pollution within the watershed and therefore requires effort outside of the watershed boundaries.

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