04-09-2015 - Laserfiche WebLink

Exhibit A-1 Description of Supplemental Scope of Work: The scope of the initial analysis was limited to a sample of land tracts to evaluate the effects of water staging associated with the FM Diversion. To effectively evaluate the potential effects of temporary water storage on agricultural lands in the staging area, study sponsors agreed to provide hydrology modeling identifying the timing and duration of water in the staging area for several flood sizes. In addition, the hydrology modeling contained water inundation for current conditions (no diversion) and water inundation with the FM Diversion. Hydrology modeling in the FM Diversion staging area was delineated into 97 individual tracks. The study sponsors and research team agreed that it would be preferred to have the study include all of the tracks, as opposed to a subset of the land tracts affected by water storage which was the original expectation. The initial hydrology modeling supplied to NDSU revealed substantial variation among the various land tracts in the staging area, and this variation will require additional time to compile and delineate the economic effects of water inundation within the storage region. The effects of water storage vary based on event size (e.g., 10-yr, 50-yr). At the point the study was initiated, the FM Diversion Authority had limited their hydrology modeling to a synthetic flood event, which serves as the design basis for the project. In other words, the flood events modeled by the FM Diversion Authority represented a compilation of water volumes and flows that would be expected based on data from several sources. However, the synthetic flood events modeled by the FM Diversion Authority does not specifically represent any actual previous flood event (e.g., 1979 event, 2006 event, 1997 event, or 2009 event). The research team gathered water flow data for the Red River in Fargo, and evaluated the data with respect to how the timing and duration of floods have varied since 1940. The evaluation was done to compare the duration of actual flood events with the synthetic events supplied by the FM Diversion Authority. The evaluation revealed that variability existed among the actual historical major floods, and the variation could have different economic consequences for agricultural producers in the storage area. The conclusions pulled from the analysis of water flows lead the FM Diversion Authority to develop additional hydrology modeling reflective of a long-duration flood (1997 like flood) and a short-duration, but high crest height flood (2009 like flood). The addition of these flood events has expanded the original scope of work and has increased the reporting requirements for the original project.