for each year of permit coverage." The linear approach expresses the rate in terms of the "amount of nitrogen and phosphorus from manure, litter, and process wastewater allowed to be applied." The narrative rate approach expresses the amount in terms of a "narrative rate prescribing how to calculate the amount of manure, litter, and process wastewater allowed to be applied. The EPA believes that the narrative approach gives CAFO operators the most flexibility. Normally, CAFO operators are subject to the terms of their permit for a period of 5 years. Under the narrative approach, CAFO operators can use "real time" data to determine the rates of application. As a result, CAFO operators can more easily "change their crop rotation, form and source of manure, litter, and process wastewater, as well as the timing and method of application" without having to seek a revision to the terms of their NPDES permits. Government assistance for compliance The EPA points to several tools available to assist CAFO operators in meeting their obligations under the CWA. First, the EPA awards federal grants to provide technical assistance to livestock operators for preventing discharges of water pollution (and reducing air pollution). The EPA claims that CAFOs can obtain an NMP for free under these grants. Recently, the annual amount of the grant totaled $8 million. Second, a Manure Management Planner (MMP) software program has been developed by Purdue University in conjunction with funding by a federal grant. The MMP is tailored to each state's technical standards (including Phosphorus Indexes and other assessment tools). The MMP program provides free assistance to both permitting authorities and CAFO operators and can be found at the Purdue University website. Lastly, the EPA notes that the USDA offers a "range of support services," including a long-term program that aims to assist CAFOs with NMPs. Debate over EPA policy Environmentalists argue that the standards under the CWA are not strong enough. Researchers have identified regions in the country that have weak enforcement of regulations and, therefore, are popular locations for CAFO developers looking to reduce cost and expand operations without strict government oversight. Even when laws are enforced, there is the risk of environmental accidents. The massive 1995 manure spill in North Carolina highlights the reality that contamination can happen even when it is not done maliciously. The question of whether such a spill could have been avoided is a contributing factor