Information about the Model

Manaaki Taha Moana (MTM) Mediated Modelling of Horowhenua Coastal Ecosystem Services: Systems Dynamics Model Description

 

Index

 

1.0 Background:
2.0 MTM Model Development:
2.1 Program Used – Stella:
2.2 Model Simulation Specifications:
2.3 Model Modules:
2.3.1 Population Pressures Module:
2.3.2 Land Cover and Use Module:
2.3.3 Ecosystem Services Module:
2.3.4 Socio-Economic Module:
2.3.5 Recreation Value of Horowhenua Module:
2.3.6 Urban Wastewater Loads:
2.3.7 Industrial Wastewater Loads:
2.3.8 Urban Stormwater Loads:
2.3.9 Pastural Farming Loads Module:
2.3.10 Horticulture and Cropping Loads:
2.3.11 Total Pollutants Loads:
2.3.12 Actions, Solutions and Agency Spend Module:
2.3.13 Indicators:
2.3.14 Major External Factors
3.0 Reports to Date

1.0 Background:

The Manaaki Taha Moana (MTM) research team is building a systems dynamics model (MTM Model) for Horowhenua District and its catchments.  The model is being developed with stakeholders during and in between the MTM project workshops. This document is a recording the development of the MTM model along the process. The ultimate goal of the Manaaki Taha Moana project is to enhance and restore ecosystems of importance to Horowhenua District(in that case study). Local iwi participants and Stakeholders will provide a robust set of perspectives into the Mediated Modelling workshops, defining the social and cultural impacts of the degradation of the health of Horowhenua District and the life force it brings to tangata whenua. Only through understanding and cooperation between tangata whenua and all stakeholders could this possibly be achieved. The tangata whenua participants, along with the MTM research team welcome the opportunity to engage in the Mediated Modelling sessions as a platform to bring this to fruition.

1.1 Team Developing the Model:

Aaron McCallion, Huhana Smith, Moira Poutama, Aroha Spinks, Nigel Thomas, Steven Mason

1.2 Model Questions:

The main question we want the model to answer. Preliminary answers from Workshop 1&2 are added.

1.     What are the 3 factors that most threaten the health of Horowhenua?

The 3 big issues (symptoms) that seem to be emerging from the workshops are:

1) Sedimentation;

2) Eutrofication;

3) Loss of things such as kaimoana, habitat loss. The inherent processes/factors that are causing these issues are: 1) increased industrial/economic activity depleting ecosystems and their services; coastal development and urban pressures and associated pollution; system not “counting” ecosystem services.

2.     What are the desired outcomes of a sustainable catchment with respect to economic, cultural, social, and environmental wellbeing?

Ecological (natural): Water that is same quality as at uppermost part of catchment, ie clear, drinkable, sustains life.

Social: Valued uses of catchment can still occur. Eg fishing; Mana-enhancing social systems reliant on the harbour, such as ability to collect kaimoana, are intact.

Cultural: Mauri of catchment is sustained?

Economic: The value of ecosystem services is accounted for in the economic system, with appropriate incentives and regulations, so that use of natural resources is sustainable and does not erode natural capital upon which the economy depends, thus enabling ongoing but sustainable “economic” activity in region.

3.     What actions can produce the most positive overall outcomes, to address root causes of problems?

Heavy “users” of ecosystems, or groups/industries that benefit from ecosystem services provided by the catchment, should also contribute to the maintenance/restoration of those ecosystems. Eg through funds set up specifically for ecosystem services, via taxation or levies on ecosystem goods and services. System adapted via incentives/taxes to encourage individuals/groups to engage in restoration efforts, or limit unsustainable use of ecosystems.

4.     What social values can we modify to effect solutions?

Better integration, so people see “whole picture” and how parts of the system influence each other – eg how economic/social/cultural activities impact on the environment, and vice versa. We want society to be conscious of the services they ARE getting from ecosystems, that they have value – so society will WANT to support them and ensure sustainable natural capital levels. Thus, people to better understanding the whole system, interactions between parts of the system, how economic/social activities impact on environment and how environment provides “services” to humans that are not necessarily “free” forever.

2.0 MTM Model Development:

2.1 Program Used – Stella:

Download a trial version

Free isee Player Version

Mapping and Modelling:

• Icon-based graphical interface simplifies model building
• Stock and Flow diagrams support the common language of Systems Thinking and provide insight into how systems work
• Enhanced stock types enable discrete and continuous processes with support for queues, ovens, and enhanced conveyors
• Causal Loop Diagrams present overall causal relationships
• Model equations are automatically generated and made accessible beneath the model layer
• Built-in functions facilitate mathematical, statistical, and logical operations
• Arrays simply represent repeated model structure
• Modules support multi-level, hierarchical model structures that can serve as “building blocks” for model construction

Simulation and Analysis:

• Simulations "run" systems over time
• Sensitivity analysis reveals key leverage points and optimal conditions
• Partial model simulations focus analysis on specific sectors or modules of the model
• Results presented as graphs, tables, animations, QuickTime movies, and files
• Dynamic data import/export links to Microsoft® Excel

Communication:

• Flight simulators and dashboards describe model components and facilitate manipulation
• Input devices include knobs, sliders, switches, and buttons
• Output devices highlight outcomes with warning flashers, text, graphs, tables, and reports
• Storytelling supports step-by-step model unveiling
• Causal Loop Diagrams present dominant feedback loops within structure
• Sketchable graphs allow easy comparison of expected results with actual simulations
• Export for NetSim support publishing and sharing model over the web using isee NetSim add-on software
• Save as Runtime option creates full-screen, runtime models
• Multimedia support triggers graphics, movies, sounds, and text messages based on model conditions

2.2 Model Simulation Specifications:

• Temporal scale: Annual time step from 1950 to 2070
• Spatial scale: Hokio Stream to South Otaki River. 

2.3 Model Modules:

• Catchment Population Pressures
• Land Use
• Ecosystem Values
• Socio Economic
• Recreational Value of Horowhenua.
• Pollutant Loads on Horowhenua
• Actions Solutions and Agency Spend
• Major External Factors
• Horowhenua Indicators
• Water Dynamics of Horowhenua and its Catchments

2.3.1 Population Pressures Module:

This module simulates the population changes from 1950 till 2070. It includes the resident population and inbound tourists in the Horowhenua catchment to calculate the effective population pressure to the region.

The population pressure is linked to the urban water demand in the water availability and use for the catchments module.

Data Inputs:

Horowhenua Catchment Population

Data Sources:

Statistics NZ - Horowhenua Population Statistics 1986-2006.

Data Calculations:

Outputs: (graphical)

• Population projections using various growth rates

2.3.2 Land Cover and Use Module:

This module simulates the predominant and projected land use and land cover changes from 1950 till 2070. It also shows the contribution of different land uses to the total sediment loads into the Horownua coast. This module also estimates the total sediment trapping. The ‘total sediment’ will be linked with ‘sediment impact on shellfish’ from the ‘Ecosystem Services’ module, ‘recreation value of Horowhenua’ module, and ‘Pollutant Loads’ from the ‘Total Pollutant Loads Horowhenua Catchment’ module to simulate the possible impacts.

Data Inputs:

• Main land use categories and their area in Ha since year as at 2008.
• Need accurate trend data of land use changes since 1950 to 2008

Data Calculations: 

Graphical Output:

Changes in Land use overtime and effect on Sedimentation/Wetlands

• Sedimentation in Tonnes 1950-2070

Data Sources:

Staticstics New Zeland 

2.3.3 Ecosystem Services Module:

This module simulates the services that ecosystems provide humans and the impact of Sedimentation, Toxins and Pollutantson these ecosystems. One way of doing this, is to place a monetary value on the 'services' that 'ecosystems' provide humans.  By placing a monetary value on these ecosystem services, their value becomes 'visible' and decision makers can appreciate their true worth. A further monetary valuation can be put on the food resource of commonly gathered species of Horowhenua. The annual harvested values of these species could be measured and the impact of food resource loss via toxins, shellfish bans and other impacts could be measured over the Scenario period (1950-2070).

Data Inputs:

Any relevant information/data associated with the following:

• Sediment Impacts on Shellfish
• Dredging Impacts on Shellfish
• Biomass and Land catch data of commonly harvested for food species in Horowhenua.
• Fish Species
• Values of Ecosystem services in USD$
•Wetland, Indigenous forest area in Ha

To be included:

• Bird Species
• Forest Health Factors
• Bio security risks
• Health and feedback loops to pollutant loading of harbour

Data needs:

• Estimates of Native and Non-Native fish population in Horowhenua.
• Annual growth rate
• Annual harvest rate
• Estimates of Native and Non-Native birds population
• Estimates of Customary and Recreational Food Gathering
• Forest Health data
• Pest eradication program data

Data Calculations: 

Outputs: (graphical)

Ecosystem valuations

Biomass valuation

Harvested valuations overtime

Data Sources:

• Statistics New Zealand Website

2.3.4 Socio-Economic Module:

Data Needs:

• Standard of living data
• Employment Data – Number of jobs, unemployment rate....
• Mining was mentioned
• Cost of unemployment
• Cost of crime
• Bio-security risk – Pest species....
• Global/National Economy
• Interest rates
• Inflation

2.3.5 Recreation Value of Horowhenua Module: This module simulates the recreational value of Horowhenua.

The recreational opportunities available on and around the catchment are a significant attraction for people to live and visit the Horowhenua region. The quality of the physical environment and leisure/recreation opportunities are some of the main reasons why people move to this area.

Data Needs: Any relevant information/data associated with the following:

• Catchment Margins
• Navigation safety
• Nutrient Loads
• Water Quality
• Environmental Food Resource Indicator

2.3.6 Urban Wastewater Loads: This module estimates the pollutants loads from all urban waste water discharges.

There are a number of urban wastewater treatment plants. As expected, they will have different amounts of loadings both in terms of quantity and concentrations of pollutants.

Data Needs:
-  List of all major pollutants to be considered from urban wastewater discharges
-  All urban discharge consents and their loading rates of identified pollutants: Quantity discharges (e.g. cubic m per day or year) and concentrations of different pollutants (g per cubic m)

Calculations Needs:
-  Aggregate the urban wastewater discharges and loadings (total quantity with weight average concentrations) per pollutant

Module Developments:
-  Further develop the module according to the identified pollutants in urban wastewater discharges
-  Populate the module with collected and estimated town wastewater discharges data

2.3.7 Industrial Wastewater Loads: This module estimates the pollutants loads from all industrial wastewater discharges.

There are a number of industrial wastewater treatment plants. As expected, they will have different amounts of discharges and pollutant loadings both in terms of quantity and concentrations.

Data Needs:
-  List of all major pollutants to be considered from Industrial wastewater discharges
-  All Industrial discharge consents and their loading rates of identified pollutants: Quantity discharges (e.g. cubic m per day or year) and concentrations of different pollutants (g per cubic m)

Calculations Needs:
-  Aggregate the industrial discharges and loadings (total quantity with weight average concentrations) per pollutant

Module Developments:
-  Further develop the module according to the identified pollutants in industrial wastewater discharges
-  Populate the module with collected and estimated industrial wastewater discharges data

2.3.8 Urban Stormwater Loads: This module will estimate the pollutants loads from stormwater from urban areas.

Data Needs:
-  List of all major pollutants to be considered from Stormwater
-  Stormwater consents
-  investment

Calculations Needs:
-  Aggregate the stormwater discharges and loadings (total quantity with weight average concentrations) per pollutant

Module Developments:
-  Further develop the module according to the identified pollutants in stormwater discharges
-  Populate the module with collected and estimated stormwater discharges data

2.3.9 Pastural Farming Loads Module: This module estimates the pollutants loads from Pastural farming sector.  The approach of ‘cows per ha’ would allow us to simulate the impact of dairy intensification (increasing stock per ha) as well as increase in dairy farming in hectares.

If there are proposed changes, it would require determining what proposed changes mean, i.e. % reduction in different pollutant loadings rates from % of dairy farming area!

Data Needs:
-  List of all major pollutants to be considered from Pastural farming sector
-  Identified pollutant loading rates, in e.g. kg N per cow per year (these loading rates should consider the attenuation coefficients!)

Calculations Needs:
-  How to calculate E-coli concentrations and loads!

Module Developments:
-  Further develop the module according to the identified pollutants from the Pastural farming sector
-  Populate the module with collected and estimated Pastural farming data

2.3.10 Horticulture and Cropping Loads: This module estimates the pollutants loads from Horticulture and Cropping farming sector.

Data Needs:
-  List of all major pollutants to be considered from Horticulture and Cropping farming sector
-  Identified pollutant loading rates, in e.g. kg N per ha per year (these loading rates should consider the attenuation coefficients!)

Module Developments:
-  Further develop the module according to the identified pollutants from the Horticulture and Cropping farming sector
-  Populate the module with collected and estimated Cropping farming data

2.3.11 Total Pollutants Loads: This module adds up all the pollutants estimated from all point and non-point sources.

2.3.12 Actions, Solutions and Agency Spend Module:

Data Needs:
-  Identify the major actions already underway in Horowhenua and its catchments; and collect their details (what, where, when, and what are the monitored or expected impacts!)
-  Identify the major proposed actions in the Horowhenua and its catchments; and estimate their details (what, where, when, and what are their expected impacts!)

Module Developments:
-  Populate the module with the collected and estimated data
-  Further develop the module according to the identified actions to be simulated.

2.3.13 Indicators: This module simulates the measures that reflect or indicate the state of the health of Horowhenua and its catchments.

What are the indicators that there is a problem? e.g. wading bird habitat – loss of bird life is an indication of a problem somewhere else in the system.

2.3.14 Major External Factors

Climatic Events - The effects of climate on vegetation and habitats across the project area results from a complex set of interactions with altitude, vegetation and land use, distance from the coast, and landforms and soils.

 

3.0 Reports to Date

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