Agenda - 06-01-2010 - 7a - Laserfiche WebLink

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Falls Lake Draft Rules Comments 6 Page 3 Given the relatively low nutrient load originating in sparsely developed, rural areas such as Orange County, a percentage -based reduction target - such as is proposed in the draft rules - will not likely result in any significant reduction in nutrient loading at Falls Lake from rural areas alone. The same percentage - based reduction in a more urban environment will likely result in a more significant reduction in nutrient loading at Falls Lake as a result of the much higher loading rates of these areas. Instead, if all entities were to meet certain nutrient loading targets, larger sources of nutrients would need to enact larger reductions than smaller sources in order to meet the target. This would seem to be more "fair, reasonable and proportionate." If such regulations were enacted, local governments which have acted to protect water quality over the years, possibly by limiting development impacts, would in fact be essentially rewarded for these past practices. Areas that have over the years promoted development with less regard to corresponding water quality impacts would likely (some may say, appropriately) have larger reductions to make in order to meet nutrient loading targets, but they would also likely have a larger tax base to pay for the required reductions. Enacting a "one size fits all" set of regulations certainly does not reward areas which in the past have enacted land use controls and development density parameters to address watershed protection. 2. Considerable concern exists about some of the parameters used in the development of the watershed model. Most significantly, we feel that the contributions of nutrients included from septic systems and sand discharge filters in the Eno and Little River subwatersheds were likely highly overestimated in the watershed model. Durham County contains approximately 3,000 sand discharge filters, while Orange County contains less than 300 of these devices. Septic systems (with sand discharge filters added in) were determined to be the main source of Total Nitrogen in the entire Eno River subwatershed by the watershed model. If this is true, this indicates that, in fact, the main source of nitrogen in these two subwatersheds is most likely not in Orange County. Furthermore, no local studies have assessed the actual rate of nutrient export to surface waters attributable to ground absorption septic systems. No local data appears to exist to support the idea that ground absorption septic systems are a significant source of nitrogen in surface waters. For these reasons, Orange County does not believe that on -site wastewater systems in Orange County represent a significant source of nutrients to Falls Lake. It should also be noted that the land cover information included in the watershed model report indicated that the majority of the land in both the Eno and Little River subwatersheds was in fact forestland, with only 17% of the Eno subwatershed and less than 10% of the Little River subwatershed even developed. Given historical development trends and policies, it is likely that these subwatersheds are more rural in Orange County than in Durham County.