Increasing abstraction of groundwater for irrigated agriculture on the Central Canterbury Plains of New Zealand has environmental effects on surface waters connected to the aquifers. There is a requirement by the regulatory authorities for design of robust rules, acceptable to the agricultural industry, for management of the groundwater resource. The aquifers constitute a 2300 km2 distributed system of stored water that responds dynamically to climatically-driven recharge and pumped abstraction. This system can be mathematically described by the eigenvalues and eigenfunctions of the groundwater flow equation. The equivalent continuous-time, discrete-space numerical groundwater models can also be represented in modal (eigenstructure) state-space format. This format forms the basis for design of system control. A simplification for practical control design is achieved by application of analytical solutions for the eigenstructure of groundwater dynamics for simple aquifers. These solutions enable spreadsheet-based computation and presentation of control options for public debate.[Show full abstract]
![[PDF]](/themes/LURA/images/mimes/b_pdf.png "PDF file"){kind=small}
