Full Costing Calculator: Swales
These calculators have been developed by the Water Environment Research Foundation (WERF) in partnership with the EPA. They determine the present and future costs associated with green roofs, rainwater catchment systems, bioretention facilities, retention ponds, extended detention basins, swales and permeable pavement. The tools allow for the production of detailed project cost reports and facilitate effective planning.
Life Cycle Costing, also known as "cradle to grave" costing, is an accounting method used to evaluate the cost of a product or system measured over its useful life. It considers operating costs, maintenance expenses, disposal costs and other economic factors in addition to initial purchasing cost.
The calculators presented here are based upon literature-derived costs and cost estimating techniques from stormwater agencies in the U.S. They offer two approaches:
- Generic (Default) Application: The user can generate costs with minimal inputs to make planning-level cost estimates. The user need only enter basic information, such as system size, drainage area and system type.
- User-entered Engineer's Estimate: The user can enter custom values for virtually every component tracked by the model, including system design and sizing, capital costs and maintenance costs. This option best reflects costs for a given geographical area and site conditions. The user can employ a combination of default and user entered values as desired.
Life Cycle Costing provides a much more accurate reflection of the budgetary demands that accompany specific projects. It recognizes that the up-front costs are only one part of the total amount of money that will need to be spent over the project's life. This approach properly emphasizes future as well as present costs in the decision-making process and the long-term impact of current sustainability investments.
