How to Use
Setting up a well-defined analysis of the system relevant for the project at hand requires input from a variety of expertise’s. Collaboration between different disciplines should provide with a coherent approach addressing all the key components of a project (natural, social and regulatory). Users of this tool need no special knowledge except their own specific field of expertise.
Phased plan process
Building with Nature designs depend on the environment in which they are planned. Different environments provide different eco-system services, which in turn provide different opportunities for BwN. Systems analysis is a tool to obtain knowledge about the ecosystem in which the BwN project will be developed. This knowledge is necessary to identify:
- long-term processes that determine ecosystem sustainability: transport, building, carrying and restoration capacities;
- ecosystem services;
- opportunities for restoration or enhancement of ecological processes and win-win solutions.
For BwN the link between environment, project and society is mainly made in terms of ecosystem services. In principle every ecosystem service can act as a target variable for the design and may help to make it more cost-effective, more multifunctional and more acceptable to stakeholders. Systems analysis required for BwN projects identifies the links between ecosystem services. Seasonal dynamics, incidents and trends are especially critical if they have an influence on essential supporting services. Often there is a lack of data, which limits the possibilities to do the necessary analysis. In that case reference studies and data should be used.
An important part of systems analysis is to identify key driving factors, their links to ecosystem processes and services and their capacities. Carrying capacities can be relevant on different system levels. The overall sand balance of the Mississippi Delta will for example determine the long-term sustainability of maintaining the present extension of wetlands and coastlines. Carrying and other capacities of the natural environment are important design variables for a BwN project. It determines limits of what can be done using natural processes. Sometimes a project can become much more cost-effective if its implementation is attuned to natural process capacities. Often, the short-term deadlines require costly engineering interventions. An eco-engineer needs to know the natural process capacities, which include:
- Transport and building capacities
Set limits to the use of natural driving forces in project design, for example:
- the (building) capacity of natural dune formation: the net dune growth depends on the beach width and orientation and wind conditions. For coastal protection projects it is important to know whether natural dune formation is fast enough in order to counterbalance sea level rise. The case of the Delfland coast shows that this is in fact the case. It is possible to build a long-term defence strategy purely on natural dune formation, provided that the conditions for dune formation are optimized;
- the (building) capacity of salt marshes: the growth of salt marshes depends mainly on silt concentrations, tidal activity and wave exposure. Salt marshes may grow with rising sea levels and may therefore provide a lasting service in the attenuation of waves and therefore to coastal protection. A BwN project may use this ability and ensure that the appropriate conditions that make this possible are met;
- the (transport) capacity of long shore currents: this capacity determines the deployment of sand along the coast in case a mega nourishment is used. The faster the deployment, the longer the coastal section that will be provided with sand.
- Carrying and restoration capacities
Determine the possible effects on ecosystems and limits to specific ecosystem services, for example:
- the (carrying) capacity of bottom dwelling communities in case of sand nourishment. In the case of foreshore nourishment, already a thin blanket of sand may kill most benthic organisms present. Bottom dwelling communities are however adjusted to occasional re-suspension and burial during storms. So in some areas dredging material is spread in a way that it simulates storm conditions and hence has limited effects on the environment;
- the (carrying) capacity of shellfish beds to withstand waves. Shell fish beds are mostly found on locations with limited wave energy. This may mainly be related to the abilities of juveniles to settle and maintain specific morphological positions. In one of the BwN projects, the growth of a shell fish bed was kick started using a biodegradable artificial structure. In this case it is important to know whether a fully grown shellfish bed will be able to maintain its position; and
- the (carrying) capacity of a coral reef to withstand temporary exposure to higher turbidity levels and sediment concentrations. This is a critical factor for the design of dredging activities in a sensitive area with corals. The lower limit to the environment sets the upper limit for the dredge plumes.
Ecosystem services can be divided into four main categories:
- Provisioning services
The most obvious, since they generate tangible and marketable products. Nevertheless, production services also depend upon supporting services that can only be identified on the basis of more in-depth understanding of population dynamics and ecosystem relations. Spawning and nursery areas are a good example with regard to fisheries. But ecosystem relations can be very complex. A notable example is the flounder. It spawns in the North Sea, to the south of the Netherlands, and larvae reach the nursery areas along the coast by freely floating with tidal currents. Critical to their transport is a slight landward undercurrent that is driven by salinity gradients present because of the inflow of fresh river water from the Rhine. A land reclamation project may adversely influence this undercurrent. Therefore, in preparation of the expansion of the Port of Rotterdam, the flounder was subject to extensive environmental impact studies.
- Regulating services
Often not readily identified, since they do not, in economic terms, deliver a marketable product. The service they provide can however be very critical, such as maintaining water quality or a wide beach that is essential to beach recreation or coastal safety. Without this regulation services costs would be necessary to deliver similar services, but with man-made installations, such as a waste water treatment plant or structures, such as a dike.
- Cultural services
Especially important for the public acceptance of a project, although they may have a concrete economic impact. These services depend upon supporting services as well. The formation of attractive beaches may determine beach front property prices, but requires an on-going long shore transport of sand. If this transport is blocked, erosion would be the result with the ultimate risk of property damage.
- Supporting services
Necessary for the production of all other ecosystem services. Some examples include biomass production, production of atmospheric oxygen, soil formation and retention, nutrient cycling, water cycling, and provisioning of habitat. Supporting services depend upon basic hydraulic and morphological processes. Supporting services are the major drivers and design parameters in most BwN projects. This is due to the fact that most interventions have an influence on hydraulic and morphological processes. In practice nearly every provisioning, regulating and cultural service is linked to processes that start in a web of interrelated supporting services. The focus is not only on fish communities, but also on their spawning, nursery and feeding areas. The vitality of mangrove forests also depends upon sedimentation processes and soil forming processes. And these areas depend upon hydrological and morphological processes. The interaction between abiotic processes and organisms merits special attention. Understanding this relation will help to identify the conditions needed to steer and stimulate colonisation, primary production and so on. It will also help to identify the way in which organisms can actively be used to steer desired morphological or soil forming processes. Pilots are conducted within BwN using shell fish. But smaller organisms, such as algae, may also play an important role in the sedimentation processes that occur on mudflats.
The steps mentioned above help to identify impacts and dependencies. The DPSIR tool is an approach that primarily focuses on impacts. But project dependencies are also very important. A project takes place in an environment that is the result of on-going processes and related ecosystem services. An impact analysis focuses on the impact of a project on this environment and vice versa. But there may be other on-going developments that influence the underlying matrix of supporting services. Examples are long-term developments in sand balances, that may be altered due to interventions in adjacent coastal areas or upstream rivers, that block sediment transport. So a comprehensive system analysis goes beyond the mere interaction of the project and its environment, but looks also into overall and general trends.
Systems Understanding Technical Guidelines
This guideline on Natural System Analysis is part of a series of Technical Guidelines on technical and socio-economic Building with Nature measures that, in combination, help to restore eroding tropical muddy coasts. These guidelines are based on insights and lessons learned during the implementation of a district scale pilot in Central Java as part of the Building with Nature Indonesia program. By sharing our lessons learned in these practical guidelines, we aim to enable replication by government agencies, the water and aquaculture sector and NGOs. Building with Nature measures need to be part of integrated coastal zone management and require a thorough problem understanding and system analysis. Stakeholders interested in replicating our approach bear full responsibility for the success and sustainability of the approach.