Cumulative Impact Assessment and Data Collection
Many commenters objected to the Corps position stated in the July 21, 1999, Federal Register notice that the Corps can monitor only those cumulative adverse effects on the aquatic environment that result from activities permitted by the Corps regulatory program. Some of these commenters said that this position is contrary to the Clean Water Act and recommended that the Corps utilize the definition of cumulative impacts found in the regulations for the National Environment Policy Act (NEPA). Numerous commenters asserted that cumulative impact analysis should include both regulated and unregulated losses of aquatic habitat within a geographic area. One commenter said that cumulative impact analysis should include all activities that affect water quality. Two commenters objected to the Corps statement in the July 21, 1999, Federal Register notice that district engineers must have clear, extensive, and unequivocal evidence that activities regulated pursuant to section 404 of the Clean Water Act or section 10 of the Rivers and Harbors Act are causing more than minimal cumulative adverse effects on the aquatic environment, not unregulated activities, before revoking or suspending the use of NWPs. One commenter stated that cumulative impact assessment should consider temporary and permanent losses of waters of the United States in a different manner. This commenter also remarked that the cumulative impact assessment must also consider both losses of waters of the United States and compensatory mitigation to determine the net cumulative adverse effects on the aquatic environment.
The Corps position in the July 21, 1999, Federal Register notice concerning cumulative impact assessment is based on the statutory requirements of Section 404(e) of the Clean Water Act. There are no other references to cumulative adverse effects in Section 404 of the Clean Water Act. The requirement for authorized activities to cause no more than minimal adverse effects on the aquatic environment applies only to general permits (including NWPs), not the entire Corps regulatory program. This position is also supported by the regulations for implementing the Section 404(b)(1) guidelines at 40 CFR 230.7. These regulations state that activities authorized by general permits can result only in minimal adverse effects on water quality and the aquatic environment (see 40 CFR 230.7(a)(3)).
The Corps scope of analysis for the purposes of NEPA is discussed in 33 CFR part 325, appendix B. The Corps can only address the impacts of the specific activity that requires a Department of the Army permit and those portions of the activity over which the district engineer has sufficient control and responsibility to warrant Federal review.
The Corps does provide different consideration to temporary and permanent losses of waters of the United States when assessing the adverse effects of regulated activities on the aquatic environment. As discussed in the NWP definition of "loss of waters of the United States," waters of the United States that are temporarily filled, flooded, excavated, or drained, but restored after construction, are not included in the measurement of loss of waters of the United States. Therefore, temporary losses would not be included in the Corps cumulative impact assessment since the affected areas would be restored as waters of the United States. When assessing cumulative adverse effects on the aquatic environment, the Corps also considers compensatory mitigation for losses authorized by NWPs, because compensatory mitigation is often required to offset losses of waters of the United States and ensure that the activities authorized by NWPs have minimal adverse effects. Corps districts assess cumulative impacts on a watershed basis. Attempting to assess cumulative impacts across the nation is not possible, or appropriate.
Two commenters supported the Corps assertion that cumulative impacts must be assessed on a watershed basis. One of these commenters said that watersheds should be defined by the 8-digit watershed cataloging units designated by the U.S. Geological Survey (USGS). Two commenters requested that the Corps develop a method to quantify potential cumulative and indirect impacts that will result from activities authorized by NWPs in a watershed. Two commenters said that district engineers must demonstrate that the use of NWPs in a watershed or geographic area will not result in more than minimal adverse effects on the aquatic environment.
As discussed in the July 1, 1998, Federal Register notice, the Corps utilizes the 8-digit hydrological unit codes developed by USGS to identify watersheds for its data collection process. However, district engineers can utilize subwatersheds within these hydrological units when conducting cumulative impact assessments. The Corps does not have the resources to develop a method to quantify potential cumulative and indirect impacts that may result from activities authorized by NWPs. If the division or district engineer determines that the use of NWPs to authorize activities within a particular watershed or geographic area will result in more than minimal individual or cumulative effects on the aquatic environment, then he or she can modify, suspend, or revoke those NWPs in that area (see 33 CFR 330.4). This is a determination that must be made by districts as they administer the Corps regulatory program in specific geographic areas.
Two commenters said that the Corps should analyze the cumulative impacts of the current NWPs and any NWPs that will be proposed in the future before issuing the new and modified NWPs. These commenters recommended that this analysis consider the efficiency of compensatory mitigation. Two commenters objected to the Corps assertion that it cannot make the individual and cumulative adverse effects determination nationally.
When the Corps issues or modifies an NWP, an environmental assessment, a finding of no significant impact (FONSI), and if necessary, an evaluation of compliance with the Section 404(b)(1) guidelines is prepared for each NWP. These items are contained in one document. This document includes an analysis of the cumulative impacts that are expected to occur during the time the NWP is in effect. This analysis also includes estimates of the amount of compensatory mitigation that will be required to offset losses of waters of the United States authorized by the NWP. We maintain our position that an assessment of cumulative adverse effects that result from the use of the NWPs cannot be made at the national level, and that the only technically sound method to conduct this assessment is on a watershed basis, through the district offices. Concurrent with the issuance of the new and modified NWPs and the final decision documents for each of the new and modified NWPs, division engineers will issue supplementary decision documents that address the impacts of the NWPs in Corps districts.
Several commenters said that Corps record-keeping methods are inadequate and that the Corps should issue quarterly public reports on wetland losses and the status of compensatory mitigation. A number of commenters recommended that the Corps establish a data collection system that tracks various types of compensatory mitigation (i.e., creation, restoration, enhancement, preservation) and monitors compliance with the goal of no net loss. Numerous commenters indicated that the Corps needs to commit to stronger monitoring and enforcement efforts.
We do not have the resources to publish quarterly reports on impacts to waters of the United States and compensatory mitigation at this time. The data collection systems for most Corps districts do not currently differentiate between the amounts of compensatory mitigation provided through restoration, enhancement, creation, or preservation. Instead, most districts track the total amount of compensatory mitigation required for Corps permits. The effectiveness of compensatory mitigation efforts is monitored by district engineers on a case-by-case basis to the extent allowed by workload and personnel resources. Therefore, we cannot collect this type of information for all activities. We are committed to strong enforcement and monitoring efforts, but enforcement and compliance efforts are limited to available district resources. The Corps permit evaluation workload must take precedence over enforcement and monitoring.
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