Storm Water Pollution Prevention Plans: California, Michigan, and South Dakota Approaches , Study notes of Civil Engineering

Download Storm Water Pollution Prevention Plans: California, Michigan, and South Dakota Approaches and more Study notes Civil Engineering in PDF only on Docsity! Quick 1 CE 491 – 002 Storm Water Management Robert Pitt, PhD, PE “Various State Storm Water Pollution Prevention Plans (SWPPP): California, Michigan, & South Dakota” Aaron A. Quick October 13, 2005 Quick 2 TABLE OF CONTENTS I. Introduction to Storm Water Pollution Prevention Plans (SWPPP) and the National Pollutant Discharge Elimination System (NPDES) II. California III. Michigan IV. South Dakota V. Summary and Conclusions VI. Works Cited Quick 5 Construction site storm water prevention plans are required when one or more acres of land are disturbed, or when specific projects are within a larger development of one or more acres. Coverage is maintained under the General Permit for Discharges of Storm Water Associated with Construction Activity. Activities subject to this permit include clearing, grading and ground disturbances such as stockpiling, or excavation. Other activities not included are regular maintenance activities performed to restore the original line, grade, or capacity of the facility. Storm water pollution prevention plans are also required with construction activities. Site specific features of this plan include site drawings with proposed construction, perimeters of project area, external discharge points and watershed areas to one quarter of a mile outside the project edges, topology, geographic features that may affect drainage patterns across the site, impervious percentages across the site including roadways, rooftops, sidewalks, empty lots, etcetera, and storm water collection and discharge points. Best management practices are also established for construction sites and must be listed. The BMPs utilized to reduce and/or eliminate storm water pollutants must be noted on the site map as well. In addition to the BMPs, monitoring by both visual and chemical methods for various pollutants must be established, performed, and documented. If discharges into an impaired waterway due to sedimentation occur, an additional sedimentation plan must be drawn up and maintained as well. Though traditional schools of thought would typically indicate that numeric discharges limits would be included in documentation associated with the California Storm Water Pollution Prevention Plans, no reliable and blanketing information was available. Given the subjective nature of various sites where storm water runoff can be monitored, each site maintains unique features that may or may not fall under criteria for another site elsewhere in the state. The most sweeping of statements found consisted of relying on the federally mandated standards of waterways in accordance with the Clean Water Act. Further, though some data was found regarding establishing runoff and run-on coefficients from Caltrans (California Department of Transportation), no set limits or parameters are set. Run-on discharges can utilize the Rational Method for determining external drainages that may cross the project site, but application is limited to areas less than 1.3 km2. Rainfall intensity standards are not specified either which seems rather counterintuitive. However, there are guides for plotting intermediate return periods and determining rainfall depths in order to calculate these intensities in millimeters per hour. Additionally, though there are no specifications on BMPs, there are listings for minimum requirements to be considered. These practices cover soil stabilization, sediment controls, wind erosion, tracking controls, non-storm water management, and waste management and materials pollution controls. Obviously, given the fact that no officially prescribed BMPs are mandated, no information can be provided about specific vendor policies, and/or the required sizing of various controls (i.e. detention ponds). Quick 6 III. MICHIGAN STORM WATER POLLUTION PREVENTION PLANS Michigan information regarding Storm Water Pollution Prevention Plans is extremely thorough. In addition to reliance on the NPDES standards from the Federal government, the Department of Environment and Natural Resources provides a wealth of information regarding required levels and tolerances of various pollutants. A brief history of storm water practices is also included and briefly reviewed here. Michigan has broken up the conventional thought patterns associated with storm water pollution and flooding into various paradigms. This stems back to the unsightly open ditches of sewage and stagnant waters in the 19th century to the current thoughts of creating sustainable and environmentally friendly areas through structural and institutional practices. Many of the current ordinances associated with Michigan’s storm waters focused first on flood detention where flooding occurred often from ice jams or snow melt in addition to large storm events. This thought pattern has progressed and now considers pollution controls and water quality concerns. Based on modeling and research, pollutants tend to decrease concentration over time with larger storm events. Through the widely accepted practice of treating the first half of an inch of rainfall, many of the pollutants are contained. Michigan scientists, however, feel this “First Flush” criterion only applies to single site scenarios. A better treatment process in their minds is to create a ninety percent (90%) treatment capability for multiple sites or for a watershed basin. By capturing and treating 90% of the storm water runoff, they presume that due to the varying time of runoff to reach the treatment point that much more of the pollutants are removed. In addition to the 90% Rule, Michigan has taken a more “holistic” approach to storm water treatment. By examining channel-forming flow features associated with bankfull conditions (which occur every one or two years), Michigan approaches control of these flows as a remedy to water quality and facilitate stream stabilization. These control measures help reduce scour at the upstream end of the reach and downstream sedimentation issues. In addition to controlling peak flows, the durations are also addressed as bankfull conditions often weaken stream banks, compounding erosion and stability problems. Continued efforts regarding storm water runoff research, modeling, treatment, and maintenance reside in the state legislature. Through governmentally imposed laws and regulations, local watershed entities can organize and prepare specific plans to aid in the integration, coordination, and implementation of these initiatives. Once these plans have been devised, site-specific “best management practices” (BMP) can be installed. Some of these as listed by the Michigan Department of Environmental Quality include rain gardens; green roofs; grass swales; and infiltration basins. These control measures help to maintain ecological stability in an environmentally friendly and consistent manner. Quick 7 Michigan storm water listings also include “acceptable limits” for various pollutants including bacteria (fecal coliform and E. coli), phosphorous, total suspended solids, biochemical oxygen demands, dissolved oxygen, and temperature and pH concerns. Table II-A below lists these pollutants along with the associated limiting discharge amounts from storm water runoff. These effluent limits are dictated by the Michigan Water Quality Standards, passed down within state Act 451. POLLUTANT ACCEPTABLE LIMITS POSSIBLE SOURCES Fecal Coliform 200 bacteria/100 mL water (monthly average) 400 bacteria/100 mL water (7-day average) E. Coli (Waters classified as full body contact) 130 bacteria/100 mL water (30-day average) 300 bacteria/100 mL water (Anytime) E.Coli (Waters classified as partial body contact) 1000 bacteria/100 mL water (Anytime) Point Source Pollution (Municipal treatment plant bypass/overflow discharges) Illicit Connections (Wastewater flowing into storm sewer systems) Non-Point Source Pollution (Agricultural runoff, animal waste, septic seepage) Phosphorous 1 mg/L (Typical – DEQ can impose stricter limits where assimilative capacities must not be exceeded) Point Source Pollution (Sewage treatment plants primarily from toothpaste, detergents, pharmaceuticals, and food-treating compounds) Non-Point Source Pollution (Lake sediment during turnover; phosphate deposits and/or rocks from weathering, erosion, and leaching; urban runoff; agricultural areas; mining operations) Total Suspended Solids 30 mg/L (30-day average) (1) 45 mg/L (7-day average) (1) Any solids that will not pass through a filter – typically there are only “narrative” limits dealing with turbidity and color, oil films, floating solids, foam, settling solids, suspended solids, and deposits. Biochemical Oxygen Demands Nitrogenous Oxygen Demand (2) Carbonaceous Oxygen Demand (2) Point Source Pollution (Wastewater treatment facilities, pulp and paper mills, and meat and food processing plants) Non-Point Source Pollution (Agricultural and urban runoff, and livestock operations) Quick 10 come in contact with precipitation or runoff waters. Proper forms are provided for requesting these exemptions and must be filed with the proper state agency. Municipal wastewater treatment plants also require permitting under the federal statutes. Municipal separate storm sewer systems (MS4s) serving all localities are required to provide verification of discharge limiting treatment procedures. Similar to the federal program mandates, South Dakota requirements pull directly from the USEPA guidelines for storm water management and list the following six control measures to be implemented: • Public education and outreach; • Public participation/involvement; • Illicit discharge detection and elimination; • Construction site storm water runoff control; • Post-construction storm water management; and, • Pollution prevention/good housekeeping for municipal operations. Unlike the construction site or industrial pollution prevention plans, municipal treatment plans are required to be submitted to the state environmental agency. Based on state legislative Act 74:54:01, basic water quality standards were established for effluent limitations and runoff concentrations. These parameters are listed in Table III-A below: POLLUTANT/CONDITION EFFLUENT LIMITATIONS Suspended Solids (1) 10 mg/L (24-hour composited sampling) Biochemical Oxygen Demand (1) 10 mg/L (5-day sample) Temperature Loading Coldwater Fisheries: +4° maximum Warmwater Fisheries: +5° maximum Incremental Hourly Gains: +3°maximum Flow Rates High Quality Fishery Waters: Not to exceed design flow of the minimum 7-day average low flow that can be expected to occur once in every 25 years Low Quality Fishery Waters: Not to exceed design flow of the minimum 7-day average low flow that can be expected to occur once in every five years (7Q5) or 1.0 cubic foot per second, whichever is greater (1) Limits for suspended solids and biochemical oxygen demand are not to exceed 17.5 mg/L in any “single grab” sampling at anytime. TABLE III-A Quick 11 South Dakota storm water prevention plan design and implementation as stated in state online references seems vague at best. Given the perceived nature of possible funding and/or manpower limitations for the state, these programs may be difficult to implement – much less enforce. This is evident in the construction site and industrial facility permitting in particular due to the “self regulating” nature of the requirements. Additionally, there are no provisions or discussions related to BMPs or control measure implementation, vendors, or proof of adequacy in regard to functionality or size of these devices. Continuing in the vague nature of the South Dakota Department of Environmental Services, there is also no discussion of discharge volume or flow rate limitations or treatment of a certain amount of runoff. Quick 12 V. SUMMARY AND CONCLUSIONS In reviewing the approach of three different states in different parts of the country, several conclusions can be drawn related to not only the various states’ interpretations of the federally mandated regulations associated with Storm Water Pollution Prevention Plans, but also their implementation procedures. Surprisingly, given the referenced materials, Michigan seemed to have the most comprehensive and readily available information dealing with a majority of the topics dealt with in the scope of this project. Many similarities pervaded each of the state approaches, obviously a result of the USEPA guidelines for SWPPP development, implementation, and maintenance. The various permits required included construction activities, industrial facilities, and municipal wastewater treatment plants in all states. Approaches at that point differed greatly based on each state’s legislative guidance policies for water quality standards. Depending on the appropriate measures from a “top-down” perspective (Clean Water Act regulatory guidelines being the most preemptive), specific state guidelines referred to those or in some cases were a little more stringent due to onsite conditions and/or extenuating circumstances in site-specific situations. Again, Michigan seemed to lead the way in the most comprehensive and “holistic” approach to storm water pollution prevention and remedy plans. Through not only water quality concerns, but also channel-forming flows and stability issues along with flood control, their approach dealt with underlying factors of contribution to pollution discharges and not only with the storm waters themselves. Further, it was noted that in all cases, very little specification was provided regarding the institution of “best management processes” (BMP). While implicitly provided for in the water quality guidelines, none of the three states covered delineated specific control measures. Instead, narrative and suggestive measures were incorporated for a wide array of solutions to be considered on a case-by-case basis. Additionally, no explicit discharge limitations for flow rates or volumes were imposed other than those established through legislative water quality standards acts. Though Michigan addressed various control methods that could be implemented, sizing and/or functionality guarantees from vendors were never mentioned across the board. Based on the results of these examinations along with the relatively wide spread knowledge of funding and manpower concerns, the storm water pollution prevention plans can be widely considered as “self regulating” procedural issues. Though routine inspections may be performed by the appropriate state agencies, given the sheer magnitude of ongoing construction projects, industrial facility waste production, and municipal treatment plants, it may be nearly impossible to ensure that water quality standards are not violated in each and every case. It must also be noted that site-specific implementation provides for an enormous “gray” area where BMP may need constant attention and remediation before appropriate discharge levels are attained to meet water quality standards.