Berkeley Street Sweeping
|SECTION 4 - PERTINENT DATA - PAGE 4|
This section summarizes data pertaining to street sweeping. Most of these sources are from special studies funded by the ACURCWP and Santa Clara Valley Nonpoint Storm Program (SCVNSP). What staff has found is that these sources do not directly address the question of "Is street sweeping effective?" To address this topic, staff had to glean information from the following pertinent data.
ACURCWP's "Loads Assessment Summary Report"
This report dated October 1991 summarizes two years of monitoring data collected from creeks and storm drains within Alameda County during both the wet and dry periods. Estimates of pollutant loads entering San Francisco Bay from Alameda County creeks are presented and compared to the pollutant loads entering from traditional point source discharges . . Conclusions also are presented about pollutant loads associated with various and use categories.
A total of 11 storm events were sampled from December 1989 through March 1991. Concentrations of total metals in the water samples were comparable with data obtained in the National Urban Runoff Program (NURP) and the SCVNSP. When concentrations of total metals for individual storm events were compared with the State Water Resources Control Board (SWRCB) objectives for acute toxicity to aquatic life, there were generally no exceedances for cadmium, chromium, and nickel. However, total copper, lead, and zinc concentrations generally exceeded the RWQCB objectives.
More than 90 percent of the solids entering the Bay is predicted to be associated with nonpoint sources. Indications are that the major portion of the nonpoint source load is absorbed, and the major portion of the point source loads enter the Bay as dissolved. The source of nonpoint loads Is predominantly from urbanized areas. Residential areas were identified as the principal source of nonpoint loads and account for two-thirds of the nonpolnt metals load. Data Indicated that toxicity is significant in storm water runoff from urbanized areas.
ACURCWP's "Storm Inlet Pilot Study"
This report dated March 1994 summarizes the results of different cleaning frequencies of storm drain inlets. The cities of Union City, Fremont, and Newark participated in the study. Sixty storm drain inlets were used to obtain data representative of the major land use types: residential, commercial, and industrial. In addition, the hopper contents of a street sweeper were analyzed to determine copper concentrations representative of the three land use categories.
The results indicate that the total annual mass of sediment collected per storm drain inlet increase with cleaning frequency. Commercial land use had the highest concentrations of copper and zinc; and industrial and residential land uses had the same concentrations. Residential land use had the lowest lead concentration, while industrial and commercial had about the same lead concentrations. Total petroleum hydrocarbons (TPH) concentrations were the highest in the residential land use. Indications are that the hydrocarbons are primarily from the combustion process (e.g., automobile exhaust}.
Data indicated that monthly cleaning would remove the greatest mass of pollutants, but this would tax existing municipal resources. Also, the cost effectiveness of cleaning inlets monthly has not been established. Therefore, the study recommends that the practice of
The study recommends that municipalities continue with the Tier I BMPs which is to inspect and clean storm drain inlets annually. For Tier II, municipalities are to inspect storm Inlets monthly during the wet season in areas suspected of containing illegal dumping, and clean as necessary. Tier I is assigned to activities that all ACURCWP permittees should implement. Tier II activities are to be implemented if it is applicable and if there are allowable resources.
ACURCWP's "Street Sweeping Literature Review/Storm Inlet Modifications Study"
A draft copy of this report dated June 1994 was reviewed by staff. The primary objectives of this study are: 1) to review previous street sweeping studies; 2) to summarize the principles of street sweeping effectiveness from these studies; 3) to provide recommendations to improve current street sweeping practices and to assess benefits of alternative efforts to the ACURCWP and 4) to summarize water quality benefits of
This study reviewed street sweeping studies conducted throughout the United States in the 1970's and 1980's on the water quality benefits of the practice. Many of the studies concluded that the practice removed significant amounts of dirt and particles from the street surface, and minor benefits to storm water quality were provided by the practice. One USEPA study concluded that street sweeping does not benefit water quality or reduce pollutant loading.
The studies reviewed showed that many of the pollutants deposited on the streets are blown off the street by winds or vehicular turbulence, and do not appear as storm water pollutants. This phenomenon limits the use of street sweeping for water quality benefits, even though a sweeper may collect large amounts of debris and street dirt.
Based on the conclusions from the reviewed studies, there are some practices that can enhance current street sweeping programs. These are: 1) reduce street sweeping to three times per week in areas now swept more frequently; 2) sweep regularly during the wet season for optimal water quality effectiveness; 3) sweep as close to the street curb as possible using manufacturers' specifications with regard to speed and maintenance; and 4) impose parking controls during street sweeping hours especially on heavily traveled or dirty streets.
The study also reviewed alternative storm inlet designs. The standard storm inlet used in Alameda County does not generally provide any kind of treatment. Storm water from the street enters into the inlet and flows directly into the storm drain pipe. Alternate inlets rely on filtration, sedimentation, or soil infiltration for treatment. Some inlets also use a grease trap to trap oil, grease, and other floatable materials. The study focused on the review of studies of modifications to existing storm inlets by using filter devices placed outside or inside the inlet; sedimentation trays and weirs; and infiltration modifications. For filters placed inside the inlet, the filter medium is contained inside a cloth/porous
The study recommendation for storm inlet modifications is to retrofit inlets to improve the water quality treatment capabilities. Due to the need for frequent and regular maintenance of these filters, only those inlets that are identified as hot spots and that can
.A copy of the booklet, BMPs for Street Cleaning, is attached in Appendix A. Practices dealing with enforced parking and discouragement of opt out are identified as Tier II BMPs. Identification of these BMPs as Tier II show that municipalities recognize the importance of these BMPs and the feasibility of implementation within their service areas.
ACURCWP's Press Release
The main objective of the Public Information Participation (PIP) Subcommittee of the ACURCWP is to get the word out about urban runoff pollution. To achieve this through the newspaper media, a series of monthly press releases were developed on seasonal
"Alameda County residents compound the problem by not moving their cars to enable sweepers to clean the streets properly. For every car that obstructs a street sweepers' path, more than 50 feet of street is left unswept--50 feet of fallen leaves, litter and other contaminants that will eventually wind up in the storm drain system. According to Dave Safreno, Alameda County Maintenance Supervisor, the problem is especially bad in neighborhoods that don't have parking controls to ·enforce sweeping schedules. "Residents living in unincorporated areas of the County where sweeping schedules are not posted can help by parking off the street, wherever possible." Safreno says."
This press release was distributed to the major East Bay newspapers. A copy of this press release is attached in Appendix B.
San Jose's "Street Sweepers Study"
This study was undertaken by Woodward-Clyde Consultants for the City of San Jose this year to determine the best type of street sweepers. The City wants to purchase six new street sweepers to replace their old Mobil broom sweepers that are about ten years old. The study performed a comparison of debris mass and concentrations picked up by the following models: Elgin broom, Elgin regenerative air, Mobil broom (new and existing models), and Tymco regenerative air. Routes were first vacuumed to "normalize" road conditions and then swept. Debris from the vacuum and sweeper operations were analyzed to determine mass and copper concentrations. A particle size breakdown was also performed to determine each model's effectiveness in picking up fines and the concentrations of copper and zinc on each particle size.
The consultant also performed a telephone survey among municipal and private street sweeping operators on noise, maintenance, maneuverability, comfort, and effectiveness. The results indicated that generally, everybody was satisfied with their street sweeper.
The draft report Is due In October 1994. Preliminary results indicate that the new Mobil broom and two regenerative air models are more effective in picking up copper than the other models.
American Sweeper Magazine
This publication is by Schwarze Industries, a manufacturer of street sweepers. 'Back issues of the magazines were checked for articles dealing with opt out. A telephone conversation with the editor of the magazine indicated that there were no similar "opt out" processes in the country. The editor is located in Washington and to his knowledge, the big urban
This article was written in Volume 3 Number 3 1994 issue of the American Sweeper Magazine. The opt out component of the street sweeping programs in Berkeley and Oakland was discussed using interviews with local officials and citizens. Streets that have opted out of the local program have to conduct their own sweeping. They are inspected visually for visible litter and debris. The argument is that I) a visual appraisal is inadequate to determine effectiveness and a numerical water quality monitoring should be taken to determine effectiveness; and 2) the opt out process does not belong in a storm water program where the monitoring is based on BMPs.
This article was written by Dr. Thomas Mumley of the San Francisco Bay Regional Water Quality Control Board to comment on the opt out process in Berkeley and Oakland. This article is in Volume 3 Number 3 1994 of the American Sweeper Magazine. The regulatory approach to storm water management in California is to not mandate any measure until it is demonstrated that the measure is effective; and to allow for an equivalent alternative. More data is needed to determine the effectiveness of mechanical sweepers to remove fine roadside particles and to develop performance standards. "Street sweeping, in and of itself, is not a solution unless it is done right; in such a way as to make the impact that needs to be made. In this, parked cars become a big issue, because if you can't get to the curb you've lost the opportunity to get to where the pollutants accumulate."
RWQCB's "Wasteload Allocation for Copper for San Francisco Bay Report"
This report dated June 1, 1993 by the RWQCB presents information supporting the adoption of an amendment to the Bay Basin Plan. This amendment would establish a more specific wasteload allocation for copper for the San Francisco Bay. The current focus of regulation of copper is on concentration Using effluent limits of 37 ug/L for deep water discharges and 4.9 ug/L for shallow water discharges. These were adopted into the Basin Plan.
The mass-based approach is proposed as an amendment to the Basin Plan. There are three steps to this process:
This report establishes mass loading limits for individual municipal and Industrial discharges, and for storm water discharges from each county. The estimated annual average loading of copper into the entire San Francisco Bay is 226,000 Ib with 82,000 (or
SCVNSP's "Source Identification and Control Report"
Santa Clara Valley Nonpoint Source (Pollution Control) Program (SCVNSP) prepared this report dated June 1992 to identify major sources of the designated metals in urban runoff, and to develop control strategies for these sources. The metals identified as critical were
Pollutant sources were identified into five classes which are:
Source Class A:
Source Class B:
Staff Telephone Conversation with RWQCB
A telephone conversation to the RWQCB staff member for the ACURCWP, Dale Bowyer, was made by staff. RWQCB wants NPDES permittees to implement effective BMPs and yet provide the flexibility for permittees to substitute or enhance other BMPs with proper justification. Because all the co-permittees of the ACURCWP have committed themselves to do street sweeping as a BMP, any modifications to street sweeping such as opt out is justified if the permittee can show that the modified practices are effective.
In our situation, the opt out process can probably be retained if the street surface (curb and gutter) can be maintained by the residents to the level performed by the street sweepers. Retaining an opt out process will require regular inspections and application of consistent inspection standards throughout to enforce the citizens' responsibilities by local resources. Staff Calculations About Removal Quantities of Copper
From Street Sweeping Program
The Streets and Utilities Division of Public Works have monthly totals of debris removed from street sweeping and storm inlet cleaning operations. These monthly totals are reported to the ACURCWP and RWQCB as part of our NPDES permit requirements starting in July 1991. A review of the annual volume of material removed through street sweeping
However, an estimate can be derived using the 3 years of street sweeping data of the amount of copper removed. from residential streets. The average monthly volume of material removed is 321 cubic yard (CY). Using a density of 7.25 Ib/CY, and a. copper
Similar calculations were performed to derive quantities of removed copper from street sweeping in the commercial and Industrial areas. The monthly volumes, densities, copper concentrations, and removed quantities for the three land uses are tabulated below. The annual quantities are 195.6 and 96 lb for the commercial and industrial areas, respectively.
From Storm Drain Inlet Cleaning Operations
A similar calculation was made to determine the quantity of removed copper by our storm drain inlet cleaning operations. The annual volume for FY91/92, FY92/93, and FY93/94 were 140; 191, and 317 cy. Using a density of 1212.3 Ib/CY and copper concentration of 0.0000274 which are associated with semi-annual cleaning operations, the quantity of removed copper is 0.90 lb/month. The average annual is about 10.8 lb. The density and copper concentration values are from the Storm Drain Inlet Study.
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