This stock and flow diagram provides a broad description of the key nutrient pathways (N and P) that exist in a dune-lake system subject to external loadings emanating from intensive agriculture.

Simulation of the water balance for the Bracciano Lake. Data from 1994 to 2003 January.

Mono Lake model from Andrew Ford's "Modeling the Environment"

This story contains a conceptual model of phosphorus cycling in a dune-lake system in the Northland region of New Zealand. It is based on the concept of a stock and flow diagram. Each orange ellipse represents an input, while each blue box represents a stock. Each arrow represents a flow. A flow involves a loss from the stock at which it starts and an addition to the stock at which it ends.

This stock and flow diagram is a working draft of a conceptual model of a dune-lake system in the Northland region of New Zealand.