NManager is a partial equilibrium simulation model developed by Motu and NIWA, the National Institute for Water and Atmospheric Research. NManager allows for integrated modelling of catchments (currently calibrated to Rotorua) for Nitrogen leaching regulation and environmental and economic outcomes. It does so by solving a three layered optimisation problem. The middle layer solves for an optimal price given farmers optimal decisions in the inner most layer. The outer most layer solves for an optimal supply of emission permits given the optimal price(s). NManager has been developed by Motu and has been used for policy formulation. NManager combines data from several external models with its own internal calculations. These models are: The Rotorua and Taupō Nutrient model (ROTAN) is a geographic information system based catchment hydrology and water quality model developed by NIWA. Farmax is a decision support model developed by AgResearch. It has been designed to assist dairy and sheep-beef farmers to maximise their productivity by simulating the profitability of farms under different management scenarios. OVERSEER is a farm management tool developed by AgResearch to help farmers maximise the productivity of their land. It also calculates nutrients lost to the environment, which has drawn the attention of regulatory bodies. For a specified regulatory system, NManager determines the pattern of nitrogen exports that will be chosen by profit-maximising landowners. Furthermore, for a specified set of environmental targets and a given regulatory scheme, NManager can determine the stringency of regulation necessary to meet those targets.
NManager is intended to reflect the complex biophysical properties of a catchment and the behaviour of landowners under regulation. It simulates the economic costs and environmental impacts associated with different approaches to nutrient management,
|State of Development||test release|
|Current Development Activity||NManager is currently being prepared for a version 2 release.|
|Outcome Areas||Economic, Environmental|
|Intended End Users||At present, single in-house specialist.|
|Spatial Extents||Local (i.e. Catchment or District)|
|Steady State or Dynamic||Steady State|
|Level of Integration||Economic, Environmental|
|Key Input Data||Micro-economic data, Land Use, Land Cover|
|Input Data Formats||Matlab|
|Key Output Data||Micro-economic data, Land Use, Runoff|
|Output Data Formats||GIS Compatible Files Matlab|
|Open/Closed Source||Open Source|
|Operating Systems||MS Windows|
|Software Needed||Matlab ArcGIS needed for data setup only|
|User Interface||No user interface|
|Ease of Use||Moderate Use requires some familiarity with Matlab code. The model is setup so that all the inputs are separate from the rest of the model for ease of use.|
|Use in Policy Process||Plan (Policy Formulation)|
Some documentation written to provide overview of NManager. The code is heavily commented to aid new developers.
|Support||Open to collaboration|
|Users Forum||Email the current model builder at Motu.|
|Methods included for calibration and validation||Data setup is external to model. NManager has been calibrated against the ROTAN model built by NIWA.|
|Methods included for managing uncertainty||No uncertainty in the model. Check the model assumptions.|
NManager solves a three layered optimization problem. The middle layer solves for an optimal price given farmers optimal decisions in the inner most layer. The outer most layer solves for an optimal supply of emission permits given the optimal price(s).
|Keywords||Nitrogen, trading, emissions, Rotorua, groundwater, water quality, dairy, sheep/beef, forestry|
|Linkages to other Models|
Water Quality Management in Lake Rotorua: A Comparison of Regulatory Approaches Using the NManager Model- http://www.motu.org.nz/publications/detail/nutrient_management_in_lake_rotorua_using_the_nmanager_model
Anastasiadis, Simon, Marie-Laure Nauleau, Suzi Kerr, Tim Cox, and Kit Rutherford. 2011. "Does Complex Hydrology Require Complex Water Policy? NManager Simulations for Lake Rotorua," Motu Working Paper 11-14, Motu Economic and Public Policy Research, Wellington.