Loading...
HomeMy WebLinkAboutPC75021 - 7/17/75 - 68th & Shingle Creek Pkwyenvironmental analysis for Cr Aesthetics a iT c In relationship with the surrounding industrial/commercial development, o the expanded transit facility will not have a significant visual impact. ' The major potential for visual conflict is between the Shingle Creek Green Belt and the transit facility. Due to the proposed park -like a quality of the Green Belt, the expanded transit facility may produce an 3 undesirable contrast as would many industrial or commercial activities W allowed in the I-1 zoning classification. 1 m The distance from the edge of the Green Belt to the expanded transit facility will be approximately 125 feet. A berm approximately 60 feet cc wide and 15 feet high runs along the edge of the Green Belt and the 0 existing site. This berm was constructed so the building is not visible from the Green Belt, and also to act as a noise barrier between the CD building and people using the Green Belt area. If this berm is extended 0 when the bus garage is expanded, it will effectively shield the Green ? r Belt from any visual, noise, and air impacts created by the MTC operations. n M M N r: Public Lands The construction of the expanded facility will not include the taking of any public land or recreation areas covered under Section 4(f) of the Department of Transportation Regulations. No districts, sites, buildings, structures, or items included in the National Register of Historic Pre- servation would be affected by the proposed construction. No construc- tion will occur on the Shingle Creek Green Belt. ME Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, ft- environmental analysis for,, Water Resources Existing Conditions The proposed site is separated from Shingle Creek by the 150-foot-wide Green Belt. At the time of planning for the existing garage, it was determined that a small depression within the Green Belt should be adapted to serve as a ponding area. The City Engineer of Brooklyn Center has indicated that the two primary considerations in developing this feature were aesthetics and water quality maintenance. It was intended that the ponding area would provide topographic relief to what is essentially a straight channel alignment throughout the Green Belt. At the same time, it was felt that the pond would serve as a settling basin during construction and operation of the facility. Water draining from the northern portion of the site discharges into a storm sewer paralleling Shingle Creek Parkway discharging to Shingle Creek. This conveyance has an approximate design capacity of 80 cfs. Preliminary calculations using the Rational Method suggest that for a storm with a recurrence interval of 10 years, the present total runoff from the site is approximately 39 cubic feet per second (cfs). Approxi- mately 19 cfs, including the runoff from the existing parking lot, road- ways and north half of the building roof, is conveyed to the Shingle Creek Parkway storm sewer. Seven cfs from the southwest corner of the roof and primarily grassed surfaces flow to the ponding area. The remainder of the total runoff proceeds as overland flow and eventually enters Shingle Creek. Drainage Modifications When the site is expanded, the impervious surface area associated with the site will be increased approximately 175 percent. It is estimated that for a 10-year storm, the total runoff will increase from the present 39 cfs to approximately 71 cfs. The runoff to the ponding area will increase from 7 cfs to approximately 42 cfs. The existing ponding area can accommodate this increased runoff. The majority of the increased flow will come from roof top laterals from the southerly exten- sion of the present building. Drainage to the Shingle Creek Parkway storm sewer will be increased from 19 cfs to approximately 21 cfs. Assessment of Probable Impacts The further development of this site, as proposed by the MTC, will result in an increase in the volume of flows in Shingle Creek, which should serve to augment low flows. However, there will not be any sig- nificant increase in peak discharge for any given storm event. 21 Q C Cn a C 1 Q c 0 w a 3 w cv w D n CD n cD CD co c� M x i N c� The Brooklyn Center area has experienced no serious flood problems at the present time and the Water Resources Management Plan for Shingle Creek2 has considered the type and level of development planned for the project area in recommending a flood control plan for the entire water - storage (24 acre-feet total) is required between County Road 10 and 69th Avenue North. However, no stormwater storage outside of the Green Belt is necessary between Freeway Boulevard and 69th Avenue North, the area of the proposed project. It should be noted that a portion of the site is below the 100 year flood level. As can be seen in Figure 4, the majority of the site is above the 843 foot flood level (as described in the Water Resources Management Plan for Shingle Creek conducted by Barr Engineering Co.). The southern portion of the site is below the flood level. The building floor eleva- tion of 847.5 is 4.5 feet above the flood level. If the proposed park- ing area is constructed at grade, portions of it will be subject to flooding once in every 100 years. Since the major concerns of building within flood plains are (1) personal safety, (2) the loss or damage of property, and (3) the potential of decreasing the holding capacity of the flood plain area and thus in- creasing downstream flooding, these points are addressed below. The building will not be subject to flooding. Therefore, personal danger or property damage in time of floods are not at issues. The grading for the building will elevate a small portion of the flood plain area above the flood level. Since the southeast corner of the proposed building site is below the 843 foot elevation, it is subject to flooding and the grading of this site would reduce the flood plain holding capacity by approximately one -eighth acre-foot. Consequently, little or no in- crease in downstream flooding will be caused due to the construction of the building. If the parking lot is built at grade, portions of the lot will be sub- ject to flooding. but no decrease in the holding capacity of the flood plain will result; and therefore, no increase in downstream flooding will occur. The Minnesota Pollution Control Agency (MPCA) is the principal agency responsible for regulating the disposal of all material having the potential to pollute the environment within the State of Minnesota. The MPCA has classified water of the state in groups based upon use. All waters within the Shingle Creek watershed are classified, "Fisheries and Recreation - Class B." This category includes water used for fishing, 2Barr Engineering Company, August, 1974. 22 Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, Inc environmental analysis for d fish propagation, bathing, or other recreational purposes. The quality of Class B water permits the propogation and maintenance of cool or warm fishing (exluding trout) and aquatic recreation of all kinds, including bathing. These standards are summarized in Table 1. Table 1 SUMMARY OF MP.CA* WATER QUALITY STANDARDS Characteristics Surface Water Classification - 2B Ammonia (N) 1 mg/l Chromium (Hexavalent, Cr) 0.05 mg/l Copper (Cu) 0.01 mg/l Cyanides (CN) 0.02 mg/l Dissolved Oxygen (April & May) 5 mg/l (June - March) 6 mg/l _ Fecal Coliform 200 MPN/100 ml Oil 0.5 mg/l Phenol 0.01 mg/l Temp. Above Natural Lakes 5 deg. F Streams 3 deg. F Turbidity 25 JTU — *Minnesota Pollution Control Agency The further development of the site will result in the creation of addi- tionla bituminous surfaces to provide for vehicular movement and employee parking (approximately 200 additional spaces). Runoff from these surfaces could contain higher concentrations of certain chemical parameters (principally petroleum products and their derivatives) than those found in Shingle Creek. However, it is not expected that these concentrations will cause a violation of MPCA water quality standards for the following reasons: �- 1. The volume of runoff from the parking lot is small in relation to the total runoff from the proposed project. 2. The City of Brooklyn Center will not allow any runoff to occur over adjacent lands. 3. All runoff to the ponding area from the parking lot will pass through a filter dam prior to the outlet conveyance to Shingle Creek. This will serve to reduce concentrations of suspended and floating solids, and additional solids may settle during the detention period. 23 Measures to Mitigate Adverse Impacts Measures to be implemented in the expansion of the site to reduce or eliminate impacts to water quality include considerations in both internal and external design, and operation of the facility. The following meas- ures will be implemented: -- Traps for inflammable wastes, grease, etc. will be provided for internal drainage such that this drainage is free of explosive or combustible solvents prior to entering the sanitary system. -- All fueling and bus maintenance operations will continue to be conducted within the garage such that any spills do not enter the storm drainage system. -- Storage tanks for the heating fuels, drained engine lubricating oils, and diesel fuel will be located outside the building and buried. Spillage tanks will be located underground near storage tank loading and unloading points. Concrete slabs will be sloped to convey any spillage to the spillage tanks. -- A small island will be constructed in the middle of the ponding area to serve as a baffle and reduce the velocity of inflow to the pond and attendant bottom scour. -- Storm water conveyance structures to the pond and from the pond to Shingle Creek will be rip -rapped at all control points to minimize erosion potential. -- Maintenance of the pond and associated structures will be assumed by the Metropolitan Transit Commission and will include regular inspection of filter dam and control structures to insure proper operation. -- Parking lot and roadway surfaces will be cleaned on a regular basis and natural vegetative growth will be promoted in the pond- ing area, particularly on banks. 24 Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, Inc environmental analysis for d Traffic Site Access Regional access to the site is provided by I-94 and T.H. 100. These two regional facilities have a full -movement interchange southeasterly of the site. A half -diamond interchange (to the east) is provided at I-94 with Xerxes Avenue North. This interchange is located west of the site. From these major routes, access to the site is gained via Humboldt Avenue and/or Freeway Boulevard to Shingle Creek Parkway. The existing roadway system is shown on Figure 5. Roadway Characteristics Interstate 94 is a four -lane, divided freeway with additional lanes near certain interchanges. In addition to the interchanges at Xerxes Avenue and T.H. 100/Humboldt Avenue, there are several interchanges with other major roadways in the area, as shown on Figure 1. Trunk Highway 100 is ,.. a four -lane, divided freeway running southwesterly from I-94, providing grade -separated access to major streets. Humboldt Avenue, which runs north from the I-94/T.H. 100 interchange, is a four -lane, undivided arterial street. Freeway Boulevard between Hum- boldt and Xerxes Avenues is wide enough to accommodate four lanes of traffic. Shingle Creek Parkway from Freeway Boulevard to the MTC garage can accommodate two lanes of traffic. The Minnesota Highway Department has a proposal which will modify the I-94 access in this area. These modifications, shown on Figure 6, will delete the interchange at Xerxes and provide a full movement interchange at Shingle Creek Parkway. The I-94/T.H. 100 interchange will be modified as shown on Figure 6. These modifications could occur by 1980. The City of Brooklyn Center, upon construction of the I-94/Shingle Creek Parkway present terminus (by the MTC site) to Xerxes Avenue. At that time, it will be constructed as a four -lane, divided roadway. Existing and Projected Traffic Volumes Existing traffic volume information for the area roadways was obtained from the Minnesota Highway Department and the City of Brooklyn Center. The average daily traffic volumes are shown on Figure 7. Also, in con- junction with the proposed I-94 modifications, the Minnesota Highway Department provided average daily traffic volume projections for 1985. These projections are shown on Figure 8. The MTC presently operates buses from the site. Based upon the existing operation with regard to directions of approach and time of day, estimates of volumes for bus and employee work trips were accomplished for a 300-bus capacity garage. These estimates were conducted on an hourly basis from 25 U C a 1 Cr c 0 D a E; w n CD n m CCD W c3 W n c� m f d cn Ikk Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, 2 W L ~ } cn W = ft- u- } N O Cl) uj c) Q o a ■� o�OQ � aoc� _v U LL co a 9 W L CC c a z(7� �U a W _ LJ 1 Lo .� )(>Q �� W Q w >( i O n o -i Q aco r c U U u. z LL a� E W aka o e V' � (n 9 } W p cv a)S _J Z c co ° •�LU (DO >QzO w > ai J Q p Q ironmental analysis for d 5:00 a.m. to 8:00 p.m. Estimates were prepared for the existing roadway system, as well as for the proposed modifications to I-94. Figure 9 illustrates the daily, morning peak hour and evening peak hour assignments for site -generated traffic on the existing roadway system. Figure 10 pro- vides the same estimates on the proposed roadway system. Probable Impact The only problems envisioned for bus traffic will be one of negotiating left turns from southbound T.H. 100 to I-94, and from the westbound I-94 off -ramp to northbound T.H. 100. During the peak traffic periods, bus traffic will experience some delay at the ramp terminals in attempting to find an acceptable gap in opposing traffic. There will also be some delay created by the present four-way stop sign control at 65th Avenue and Humboldt Avenue. However, none of these problems are considered to be so major that changes are necessary. The roadways in the vicinity of the site all have sufficient capacity to accommodate the site -generated volumes. 31 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc uj w W � I- N � - zoo C?C o W Z CD LL QLL a W Q z < w co n �■� U) f— W —1 0 6 O W � W } cn W Q Q CL W s oo CLIJ LL Q Q t W a Q w �^ c Q ~ccc L-,Jj _ cn �-- a o environmental analysis for d Air Quality! Meteorology The air quality of a given location is directly affected by the meteo- rological characteristics of the area. Wind direction and speed, atmo- spheric stability, mixing heights, and fog conditions are all meteorolog- ical phenomena which affect the transport and dispersion of air contam- inants. The Minneapolis metropolitan area is situated on a gently rolling plain where the Minnesota and St. Croix Rivers join the Mississippi River. The generally level topography has minor impact on weather and air flow which is favorable to the dispersion of air contaminants. The climate of the area is controlled by the interrelationship of con- tinental polar air masses and warm moist air masses from the Gulf of Mexico. As a result, there exists a tendency to extremes in all climatic .features. The wind speed in the Minneapolis area averages just over 10 miles per hour with little variation from month -to -month (see Table 2). Table 2 MONTHLY AVERAGE WIND SPEED AND DIRECTION Month Wind Speed (mph) blind Direction January 10.5 Northwest February 10.7 Northwest March 11.3 Northwest April 12.5 Northwest May 11.5 Southeast June 10.6 Southeast July 9.3 South August 9.1 Southeast September 9.9 South -- October 10.5 Southeast November 11.1 Northwest December 10.4 Northwest Average 10.6 Northwest 35 Q c Cn a (1)" U c 0 a� a 3 w 5� CD D 0 m n co M co co n c� M d m K Cn c� The prevailing wind is from the northwest in the winter and from the — southeast in the summer (see Figure 11). Lower wind speeds are more frequent at night, occurring at less than eight miles per hour from 40 to 50 percent of the time (see Figure 12). The prevailing direction of winds of less than eight miles per hour is southwest in the winter and — southeast in the summer. Atmospheric stability is used as a measure of atmospheric turbulence. Turbulence is mainly dependent upon three factors: surface roughness, the vertical rate of increase of wind speed, and the vertical tempera- ture profile. Temperature inversions, which define the height of the mixing layer, usually occur at night and more frequently in the winter when the sky is clear and the wind speed is low. Clear skies allow the earth's surface to radiate and cool at a fast rate, thereby cooling the air near its surface. The cool air at the surface is then restricted from vertical mixing by the warmer air above it. The Minneapolis area has a high percentage of cloud cover in the winter, more than 50 percent of the time. This mitigates the formation of low level nighttime inver- sion layers. During the fall -winter months when stagnant conditions occur more fre- quently, maximum carbon monoxide concentrations may be expected. Winds of low speed are most likely to prevail from the southeast. Minneapolis -St. Paul Air Quality Control Region -- Motor vehicles are a major source of air pollution in urban areas. According to the Minnesota Pollution Control Agency's Implementation Plan of 1971, 10 percent (by weight) of the particulates, three percent of the sulfur dioxide, 56 percent of the nitrogen oxide, 97 percent of the carbon monoxide, and 78 percent of the hydrocarbons emitted in the Minneapolis -St. Paul Air Quality Control Region (AQCR) are from trans- portation sources. Therefore, in evaluating the air quality impact of a project such as the one being examined, the greatest potential impact on air quality is likely to come from transportation sources. In Minnesota, as for other states in the nation, a priority classifica- tion for each pollutant by AQCR has been developed according to the — degree of pollution present. The classification is based on measured ambient air quality in the area of maximum pollutant concentration. For the Minneapolis -St. Paul metropolitan area, sulfur dioxide, parti- culates, and carbon monoxide were classified Priority I (highest priorty), and nitrogen oxides and oxidants were classified Priority III (lowest priority). 36 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc _ z TM LLo 00 r o 0 }U L LV = aL Ud z cnC W .i: Z C7 (n _c aULu J W J U U W F- W U uj W z W — z Z r r W 7 � C7 a tun*) U H z o L1J O U W a NLL a r 0 (n 5: �- p oo z W (L Q m � a a� o U) U. § J V N J O r Q a N o cn O CV T O fl a Q � O W z = z_ O V N LO M Hd W 8 NVHI SS31 3 W it dO lN3OH3d environmental analysis for d The priority classifications are an indication of the ease or difficulty the Minneapolis -St. Paul AQCR has in attaining and maintaining the ambient air quality standards. The national standards shown in Table 3 are minimum requirements that must be met within a specific timetable. However, the states may establish more stringent standards as Minnesota has done in the case of sulfur dioxide, carbon monoxide, and oxidants (see Table 4). Receptor Identification and Description A receptor can be defined as any place where people might be exposed to pollutants for time periods consistent with the standards. The receptor is a key element in determining the impact of any source of air contam- ination. For purposes of this study, five receptor sites were selected as being most vulnerable to air pollution from site -generated traffic. Carbon monoxide concentrations at these sites have been determined for existing and for additional traffic generated by the MTC garage. Due to the proposed major interchange modifications with I-94, these recep- tor sites have been analyzed for the two years, 1976 and 1980. For 1976, the existing roadway system is utilized, while for 1980, the pro- posed roadway system is used. 0- c CA a C" v c 0 a 3 w 5' CD w n CD n CD m co n c� c� on c� Table 3 _ FEDERAL AMBIENT AIR QUALITY STANDARDS EPA) rimarykll Secondary<<) Pollutant hording of Standard Standard Standard r Particulate Matter Annual Geom. Mean Concentration 75 ug/m3 60 ug/m3 Max. 24-Hr. Concentration 260 ug/m3 150 ug/m3 Sulfur Oxides Annual Arith. Avg. Concentration .03 pRm .02 ppm _ (80 ug/m ) Max. 24-Hr. Concentration .14 pRm .10 p3pm (305 ug/m ) (260 ug/m ) Max. 3-Hr. Concentration -- .50 ppm (1,300 ug/m3) Carbon Monoxide Max. 8-Hr. Concentration 9 ppm 9 5m (10 mg/m ) (10 mg/m ) _ Max. 1-Hr. Concentration 35 pp3m 35 5m 40 mg/m (40 mg/m ) Photochemical Oxidants Max. 1-Hr. Concentration .08 ppm .08 PT (160 ug/m ) (160 ug/m ) ._ Hydrocarbons _ (Less Meth.) Max. 3-Hr. Concentration .24 pRm .24 p�m (6:00-9:00 A.M.) (160 ug/m ) (160 ug/m ) Nitrogen Oxides Annual Arith. Avg. .05 5m .05 HIT! r. Concentration (11 ug/m ) (100 ug/m ) Hydrogen Sulfide (At present, there is no federal standard for H2S.) (1)Primary standard: Enforcement by Summer, 1975 (2)Secondary standard: No time limit on enforcement. ` 40 Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, Inc _ environmental analysis for d ,- Table 4 MINNESOTA AMBIENT AIR QUALITY STANDARDS _ Primary Secondary Pollutant Wording of Standards Standard Standard Particulate Max. annual geometric mean. 75 ug/m3 60 ug/m3 — Matter Max. 24-hr. concentration 260 ug/m3 150 ug/m3 not to be exceeded more than once per year. Sulfur Max. annual arith. mean. .02 ppm .02 pp Oxides (60 ug/m3) (60 ug/m ) Max. 24-hr. concentration .10 ppm .10 pp not to be exceeded more (260 ug/m3) (260 ug/m ) than once per year. Max. 3-hr. concentration .25 pp .25 ppm not to be exceeded more (655 ug/mI) (655 ug/m3) than once per year. .., Carbon Max. 8-hr. average not to 9 pp 9 pp Monoxide be exceeded more than (10 mg/m) (10 mg/m) once per year. Max. 1-hr. concentration 30 pp 30 ppm not to be exceeded more (35 mg/MT) (35 mg/m ) than once per year. �^ Photochemical Max. 1-hr. average not to .07 ppm .07 pp Oxidants be exceeded more than (130 ug/m3) (130 ug/m ) once per year Hydrocarbons Max. 3-hr. concentration .3 ppT .24 ppm (less Meth.) (6:00 to 9:00 A.M. not to (200 ug/m ) (160 ug/m ) be exceeded more than once) Nitrogen Max. annual arith. mean. .05 pp .05 pp Oxides (100 ug/m ) (100 ug/m ) Hydrogen 1/2 hr. average not to be .05 pp P) Sulfide exceeded over two times (70 ug/ .., per year for primary standard. 1/2 hr. average not to be .03 ppm exceeded over two times (42 ug/m3) in any five consecutive days for secondary w standard. 41 CT C CA a W Q c 0 w a CD D w n CD n CD CD CD 5' c� n 1 M m cn The following sites were analyzed (see Figure 13): -- Receptor 1. Single-family residential area in the southeast quadrant of the intersection of Humboldt Avenue North and 65th Avenue North. The receptor was considered to be 100 feet east of Humboldt Avenue and 50 feet south of 65th Avenue. -- Receptor 2. Commercial development in the southwest quadrant of _ Humboldt and 65th Avenues North (Freeway Boulevard). The receptor was located in the parking lot of the motel approximately 50 feet south of Freeway Boulevard and 200 feet west of Humboldt _ Avenue. -- Receptor 3. Industrial/office area in the northeast quadrant of Freeway Boulevard and Shingle Creek Parkway. The receptor is considered to be 50 feet east of Shingle Creek Parkway and 200 feet north of Freeway Boulevard. -- Receptor 4. Athletic field north of the Brooklyn Center High School. The receptor was considered to be 100 feet east of Humboldt Avenue and approximately 300 feet north of 65th Avenue. -- Receptor 5. Tennis courts east of the Brooklyn Center High School. The receptor was located 150 feet north of 65th Avenue and approximately 400 feet east of Humboldt Avenue. — The California Line Source Model was used in this st�jy to estimate CO levels along the roadways affected by site traffic. A wind speed of _ one meter per second blowing at an angle of 22.5 degrees from the road- way, and Pasquill-Turner Stability Class F (extremely stable) were con- sidered worst case conditions with respect to the receptor sites. _ Modeling for Ambient Conditions In order to determine the impact of the MTC garage on the local air quality, it is necessary to establish ambient air quality conditions for the analysis years (1976 and 1980) without the usage of the site by buses. By projecting normal increases in traffic volumes, utilizing projections by the Minnesota Highway Department, and application of the line source model to those volumes, impact of non -site traffic on local air quality can be determined. When these CO pollution levels are added to general background concentrations, ambient air quality conditions can be defined. (3)FHWA: Air Quality Manual 42 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, I M r Q± J Cc L Q04 dWQ r . �.. W p �- Q cc The projected maximum one -hour traffic volumes used for the analysis years 1976 and 1980 are shown on Figures 14 and 15 respectively. The CO concentrations at each receptor were calculated using the worst case assumptions. Table 5 presents the concentrations resulting from the highest anticipated hourly volumes of non -site traffic. Table 5 WORST CASE ONE -HOUR CO CONCENTRATIONS (PPM) ATTRIBUTABLE TO NON -SITE TRAFFIC CONDITIONS, 1976 AND 1980 Receptor One -Hour Concentrations 1976 1980 1 5.5 2.7 2 2.1 1.8 3 0.6 1.7 4 2.8 1.8 -- 5 1.5 0.9 The general background concentrations were determined using the metho- dology outlined in Appendix C. When peak background levels of CO are added to traffic contributions shown in Table 5, the following base line CO concentrations result as shown in Table 6. Table 6 TOTAL WORST CASE ONE -HOUR CO CONCENTRATIONS (PPM) AMBIENT CONDITIONS, 1976 AND 1980 Traffic Contribution Background Total Receptor 1976 1980 1976 1980 1976 1980 1 5.5 2.7 9.3 4.8 14.8 7.5 2 2.1 1.8 9.3 4.8 11.4 6.6 3 0.6 1.7 9.3 4.8 9.9 6.5 4 2.8 1.8 9.3 4.8 12.1 6.6 ` 5 1.5 0.9 9.3 4.8 10.8 5.7 Probable Local Impacts Impacts on the local air quality will be of three types: construction impacts, mobile source pollutants associated with site -generated traffic, and point source pollutants associated with the operation of the heating plant for the garage. 44 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc _ environmental analysis for d Preparation of the site for expansion of the existing facility produces two sources of air contaminant emissions. They are exhaust emissions from construction equipment and fugitive dust generated from material movement. The emissions produced during site preparation are of short- term, terminal duration, and are not considered in detail. Construction of the expanded facility will produce similar emissions to those en- countered in site preparation. Site -generated traffic impacts on local air quality (CO levels) are largely dependent on the direction of approach of that traffic. Using the distribution of site -generated yearly peak -hour traffic volume pro- jections for this site (Figures 14 and 15), and the California Line Source Model as applied to existing conditions, the CO levels for worst case conditions were calculated. The results of this modeling are shown in Table 7. The effect of site -generated traffic on overall CO levels is not significant enough to justify a determination of eight - hour concentrations. Table 7 WORST CASE ONE -HOUR CO CONCENTRATIONS (PPM) RESULTING FROM SITE AND NON -SITE TRAFFIC -- 1976 AND 1980 Background CO Concentrations Non -Site Site Total Receptor 1976 1980 1976 1980 1976 1980 1976 1980 1 9.3 4.8 5.5 2.7 0.7 0.1 15.5 7.6 2 9.3 4.8 2.1 1.8 0.6 0.0 12.0 6.6 3 9.3 4.8 0.6 1.7 0.6 0.4 10.5 6.9 4 9.3 4.8 2.8 1.8 0.0 0.0 12.1 6.6 5 9.3 4.8 1.5 0.9 0.0 0.0 10.8 5.7 In Table 7, the CO concentrations estimated to be emitted by traffic (bus and employee) attributable to an expanded facility are shown as site CO concentrations. It should be noted that for the worst case conditions at all receptors for both analysis years, the concentrations caused by site -generated traffic are less than one ppm. w The total CO concentration includes all non -site traffic, site traffic and background concentrations. The Minnesota standard of 30 ppm maxi- mum one -hour concentration is never threatened, and except for receptor 1 in 1976, the calculated concentrations do not equal fifty percent of the standard. 45 Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, W W F- J 0 ii X ao D o =LL? o �_ CO W a ld w �' 2 �■■ r— O F- c/) LU —j z N W W 5;°C>z X =LL LLz o W a W w ■ � 4m w r-0E-cn C - a�Ei ° :01 N a a) a� E y y w 2 E i o m� �'M z z CC m -0 0 O ironmental analysis ford Point source emissions will be associated with operation of 5 overhead heaters which will heat the building during the winter. Aside from the ambient air quality standards shown in Tables 3 and 4, point sources are required by the Minnesota Pollution Control Agency to demonstrate compliance with MPCA regulations in order to obtain an operating permit. For space heaters of the type proposed for use in the MTC garage, there are three applicable emission standards: 1. Four/tenths of a pound of particulates per one million BTU 2. A maximum of two percent sulphur content of fuel used 3. Twenty percent opacity limitation The heaters will be fueled by an interruptable source of natural gas, with propane gas backup. Therefore, no violations are anticipated. Probable Regional Impacts Hydrocarbons and oxides of nitrogen play a key role in the formation of photochemical oxidants and ozone. A complex atmospheric reaction occurs which is dependent upon the relative quantities of reactants and the presence or absence of sunlight and humidity. The present analytical capability for simulating these complex interrelationships does not lend itself to a quantitative technique for evaluating the impact of an indi- vidual source on ambient concentrations of photochemical pollutants. Although methods of analyses may be less sophisticated than is desirable for reactive pollutants, such approaches as are available indicate a need for broad -scale management of air quality. As part of a broad -scale management plan, the Transportation Control Plan for the Minneapolis metropolitan area considers the provision of a convenient and efficient mass transit system which lowers the total vehicle miles of travel (VMT) essential. In order to expand service to the north and northwest metropolitan area, a bus garage is necessary to store buses as near as possible to their points of origin (A.M.) and destination (P.M.). The Metropolitan Transit Commission, in their search for an appropriate site for this facility, used minimization of distance and time (access to freeways and expressways) to points of bus route termination as criteria for site selection. This site satis- fies both. The minimization of VMT through mass transit service expansion is ac- complished by reducing the number of work trips and also the number of park -and -ride trips. Emissions of CO and HC from diesel buses are near- ly the same as private automobiles. Emission of oxides of nitrogen from buses is only seven to eight times higher than those from autos. Consid- ering an average auto occupancy rate of 1.55 persons/vehicle, only 12 to 15 people taking the bus instead of autos would justify its use in terms of air quality. When total distance traveled by these 12 to 15 people is used to adjust these figures, even lower bus occupancy can be justi- fied on the basis of air quality. The regional impact can thus be con- sidered an enhancement. 49 a C a a c 0 a� a 3 w CD W 0 M 0 CD .. m to F n c� 0 d f m Mitigating Measures Because the impact of the MTC facility on air quality will be minimal in the local area, and may even lower total emissions at the regional level, mitigating measures are not essential to attain or maintain either Minnesota or National Air Quality Standards. However, any efforts to improve traffic flow and/or distribute traffic more evenly around the site will alleviate pollution concentrations at the receptors, while provision of more and better mass transit will continue to improve regional air quality. If the berm along the westerly edge of the site is extended when the bus garage is expanded, the air quality on the _ Green Belt adjacent to the facility will be about the same as the "Site Traffic" conditions noted in Table 7 for Receptor 3. .. 50 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, In environmental analysis ford Noise Existinq Conditions The noise environment in the vicinity of the facility site is dominated by traffic generated noise from Interstate 94 and the local street sys- tem. A field inspection of the area surrounding the site and an examina- tion of the existing and future bus approach and departure routes indi- cated the land uses most susceptible to impacts from site related noise were the single-family residential areas along Humboldt Avenue North and along Xerxes Avenue North. The first area includes the single-family homes just east of Humboldt Avenue North, between 65th Avenue North and I-94 (along the frontage road), and the second area involves the single- family homes on either side of Xerxes Avenue North just south of I-94. Noise monitoring stations were located in these two areas to obtain representative data on ambient conditions. Additional monitoring sta- tions were also located at other less susceptible areas in the site vicinity. These stations provided additional data on general background noise levels as well as specific traffic generated noise levels. Figure 16 indicates the noise monitoring locations. Locations B, C and E are in residential areas, while A is an industrial area, and D is in a park. Noise measurements were taken at various times during the day on January 14 and 15, 1976 at each of the above locations. In addition, the ambient noise levels were predicted (calculated) for the critical periods of site generated traffic. The methods for measuring and calculating ambient traffic generated noise levels is discussed in detail in Appendix D. The ambient noise levels estimated by these two procedures are pre- sented in Table 8 along with the applicable noise standards as specified by the Minnesota Noise Pollution Control Regulations. The standards are a function of the intended activity in the area and thus vary for land - uses and daytime (7 a.m. to 10 p.m.) or nighttime (10 p.m. to 7 a.m.) conditions. An analysis of the estimated ambient noise levels between 6:00 a.m. and 7:00 a.m. indicates locations B and C experience exterior nighttime noise levels in excess of the standards by 3-4 dBA under. present condi- tions, while the exterior noise levels at D and E exceed the nighttime '- standards by 1 dBA. Typical frame homes of the type involved will re- duce exterior noise levels by 10-15 dBA with windows open and 20-25 dBA with windows closed. Thus, the resulting nighttime interior noise levels at all receptor locations should be below the typically specified bedroom standard of 45 dBA. Except for Location D, the daytime exterior noise levels are below the standards. Location D represents only the perimeter area of Grandview Park adjacent to TH 100, and not a significant portion of the total park area. The main activity areas are not subject to these excessive noise levels. 51 ar C Cn a C' iT c 0 0 a 3 w 5� CD a� D n m n CD D CD cc c� n i Cn Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, I c r (v z i. 0 0 0 .� Lu E M000 �� z2-j Table 8 AMBIENT NOISE LEVELS (EXISTING) dBA* _ Time Period _ 6-7 A.M. 3-4 P.M. 6-7 P.M. Receptor M(1) C(2) S(3) M C S M C S r A L50(4) 55 49 75 44 48 75 -- 49 75 L10(5) 63 61 80 62 60 80 -- 61 80 17 s� L50 53 54 50 53 54 60 -- 54 60 L10 58 62 55 58 65 65 -- 62 65 C L50 50 54 50 -- 54 60 49 54 60 L10 53 59 55 -- 60 65 53 59 65 D L50 -- 66 65 -- 67 65 63 66 65 L10 -- 71 70 -- 74 70 68 73 70 E L50 47 47 50 -- 48 60 -- 47 60 L10 53 56 55 -- 56 65 -- 56 65 (1)Measured (2)Calculated (3)Standard NPC-2 of the Minnesota Noise Pollution Control Regulations for Exterior Conditions (4)L50 = Noise level exceeded for 50 percent of the time period under analysis. (5)L10 = Noise level exceeded for 10 percent of the time period under analysis. *Includes operation of 80 buses assigned to garage. 54 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, environmental analysis for d ._ a' C Future Conditions With the expansion of the bus garage facility, additional site related Cn ' traffic will result in increased noise levels. In addition, the major C modifications to the surrounding roadway network currently planned will also have an effect (both positive and negative) on future noise condi- tions. To assess the effect of these changes on the noise environment, su estimates of future noise levels were made at each location. The esti- a mates were made for each critical time period for three different con- 3 _ ditions: W 5' 1. The expansion of the existing facility to a 150 bus capacity using CD the existing roadway network. This will occur in 1976. 0 2. The expansion of the facility to a 300 bus capacity using the exist- 0 ing roadway network. �. CD 3. The 300 bus capacity garage with the proposed 1985 roadway network. The results are presented in Tables 9, 10, and 11. ? Probable Noise Impacts of the Proposed Facility n A comparison of projected noise conditions to existing noise conditions A as well as the applicable standards was made to assess the probable impacts of the increased noise levels. For the purposes of the assess- V ment, noise levels 0-5 dBA above the standard were assumed to represent a minor adverse impact while an excess of greater than 5 dBA was assumed to represent a major impact. Also, any increase of 5-15 dBA above ` ambient conditions would represent a minor adverse impact hile an in- cn _. crease of more than 15 dBA would represent a major impact. 4) Both of these criteria were applied to the projected noise levels at each loca- tion with the greater of the two assessed impacts taking precedent. On this basis, Location B will continue to experience a major adverse external noise impact during the 6-7 A.M. period for all conditions analyzed. However, the expansion of the bus garage represents an in- crease of only 2-3 dBA, so the major impact is created by non -site traffic. Although the exterior noise levels represent a major impact between 6 A.M. and 7 A.M., the interior noise levels should still be below the acceptable 45 dBA level. Minor noise impacts are assessed at sites C, D and E for this early morning period under all conditions. However, the existing levels indicate minor impacts occur now, and site traffic does not significantly influence noise levels at these locations. (4)General Criteria for Evaluating Noise Impacts as suggested in NCHRP Report 117. 55 Table 9 ESTIMATED NOISE LEVELS (dBA) 150 BUS FACILITY AND PRESENT ROADWAY NETWORK Time Period — 6-7 A.M. 3-4 P.M. 6-7 P.M. Receptor C(1) S(2) C S C _ S — A L50(3) 52 75 49 75 52 75 — L10(4) 64 80 61 80 64 80 B L50 54 50 54 60 54 60 L10 64 55 65 65 63 65 — C L50 54 50 54 60 54 60 r L10 59 55 60 65 59 65 D L50 66 65 67 65 66 65 L10 71 70 74 70 73 70 E L50 47 50 48 60 47 60 — L10 56 55 56 65 56 65 (1)Calculated (2)Standard NPC-2 of the Minnesota Noise Pollution Control Regulations — for Exterior Conditions (3)L50 = Noise level exceeded for 50 percent of the time period under analysis. r` (4)L1O = Noise level exceeded for 10 percent of the time period under analysis. -� 56 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc _ environmental analysis for d Q c Table 10 ESTIMATED NOISE LEVELS (dBA) N 300 BUS FACILITY AND PRESENT ROADWAY NETWORK Q c Time Period o �. 6-7 A.M. 3-4 P.M. 6-7 P.M. w Receptor C(1) S(2) C S C S a 3 w L50(3) 59 75 57 75 58 75 CD L10(4) 70 80 67 80 69 80 a� 0 B CD L50 56 50 54 60 56 60 m L10 66 55 66 65 66 65 ? _. C co L50 54 50 54 60 54 60 n L10 59 55 60 65 59 65 1 M D .,,. L50 66 65 67 65 66 65 L10 71 70 74 70 73 70 Cn E L50 47 50 48 60 47 60 L10 56 55 56 65 56 65 (1)Calculated (2)Standard NPC-2 of the Minnesota Noise Pollution Control Regulations for Exterior Conditions (3)L50 - Noise level exceeded for 50 percent of the time period under analysis. (4)L10 = Noise level exceeded for 10 percent of the time period under analysis. *A Table 11 ESTIMATED NOISE LEVELS (dBA) 300 BUS FACILITY AND PROPOSED ROADWAY NETWORK Time Period 6-7 A.M. 3-4 P.M. 6-7 P.M. Receptor C(1) S(2) C S C S ._ A L50(3) 59 75 57 75 58 75 r L10(4) 70 80 67 80 69 80 B L50 56 50 64 60 56 _ 60 L10 65 55 73 65 65 65 _ C L50 55 50 59 60 55 60 _ L10 60 55 62 65 60 65 D L50 66 65 67 65 66 65 L10 71 70 74 70 73 70 _ E L50 47 50 48 60 47 60 L10 56 55 56 65 56 65 (')Calculated (2)Standard NPC-2 of the Minnesota Noise Pollution Control Regulations _ for Exterior Conditions (3)L50 Noise level exceeded for 50 percent of the time period under _ analysis. (4)L10 = Noise level exceeded for 10 percent of the time period under analysis. ME Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, environmental analysis for d An examination of future daytime conditions indicate Location B will experience only minor noise impacts with the existing roadway network. The ultimate expansion of the bus facility results in an increase of 2-3 dBA in the noise levels for this site under the existing roadway conditions. A more significant increase in noise levels is anticipated with the future proposed roadway network. This increase in noise levels is not attributable to site traffic as this is substantially reduced from the other future conditions. Rather the increase is almost entire- ly due to projected increases in through traffic volumes. Location D will continue to experience minor noise impacts during the daytime hours in the future as it does presently. Site traffic does not significantly influence the noise levels at this location. Also, the impacted areas represent only a small portion of the total park land involved and does not affect any major activity area. Noise levels were also calculated in the vicinity of the Brooklyn Center Village Hall (500 ft. south of I-94, 50 ft. west of Shingle Creek Parkway) under the proposed 1985 roadway network and 300 bus _ garage conditions. The increased traffic volumes on I-94 and the through traffic on Shingle Creek Parkway would result in approximate L50 and L10 noise levels of 64 and 70 dBA compared to existing L50 and L10 noise levels of 57 and 61 dBA approximately. The applicable L50 and LlO noise standards would be 65 and 70 dBA. The noise attributable to site related traffic represents an insignificant portion of the total anticipated noise levels at this location under the projected traffic conditions. In addition to noise related to the site traffic, the construction _ activity related to the garage expansion will result in increased noise levels immediately adjacent to the garage site. The noise levels will vary according to type and location of construction. Table 12 lists the typical noise levels at a distance of 50 feet from the location of a particular onsite activity. Table 12 TYPICAL NOISE LEVELS ASSOCIATED WITH ON -SITE CONSTRUCTION Construction Average Noise Energy Standard Activity Level, dBA Deviation, dBA Ground Clearing 84 9 Excavation 89 6 Foundations 77 4 Erection 84 9 Finishing 89 7 59 Q c W a Cr c 0 a� a 3 a� m a� n m n c� m co c� m a� i d M The location of on -site construction activity will vary considerably. The clearing and excavation and finishing activities will occur for a short period of time on almost every section of the site while the con- tinuous foundation and errection activity will take place in the center of the site. Noise generated by on -site activity is not anticipated to have any adverse impact on adjacent lands. Most of the activity will take place on the eastern portions of the site facing non noise susceptable areas. Activity will be sufficiently removed from the proposed open space area along Shingle Creek so as to eliminate the potential for significant noise impacts. Likewise, construction activity will be sufficiently removed from adjacent lands. Also, the construction noise will be sporadic and only a temporary condition. Thus it is not expected to represent a potential for significant noise impacts. Measures for Mitigating Noise Impacts The only major noise impact related to the increased site generated traffic is at the houses along Humboldt Avenue North between 65th Avenue North and I-94. The existing early morning external noise levels cur- rently exceed the NPC-2 standards, and the site generated traffic for the ultimate facility will increase the early morning external noise levels by 2-3 dBA. However, the interior noise levels should be below standards. Because the increased noise levels associated with the expanded bus garage are a small proportion of the total, the only economical mitigating measure is the rerouting of bus traffic. This measure has been incorporated into the facility plans with the 1985 roadway network. Site traffic is diverted from the Humboldt Avenue North interchange to the proposed Shingle Creek Parkway interchange. However the ameliorating effect of this is offset by increased through traffic volumes on Humboldt Avenue. If the berm along the western edge of the site is extended when the facility is expanded, the Green Belt will be effectively shielded from the noise associated with operation of the bus garage and maintenance facility. W Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, environmental analysis ford — Energy Consumption Q c N a — The existing facility is heated with five ceiling -mounted, gas -fired c space heaters. The gas is supplied by the Minneapolis Gas Company on an o interruptible basis. Propane gas is used as the back-up fuel and is — stored in 60,000-gallon underground tanks. Continuous ventilation is provided by electric motor -driven fans. The estimated annual energy o- requirements for the existing facility are 24,658,000 BTU's for heating 3 and 2,532 KWH's for ventilation. No construction plans have been prepared for the expanded facility. CD w However, personnel at the MTC indicate that when the proposed expansion — occurs, the backup fuel supply will be changed to fuel oil. A boiler CD will be added, and the existing space heaters will be converted to heat 0 M exchangers. Gas fired water heaters will be used. The annual estimated — fuel requirements for the total facility (existing and proposed) are CD 70,000 gallons of fuel oil, and 25,000 cubic feet of gas. to n 1 Sl 1 d N -. Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, environmental analysis for d _ 4. UNAVOIDABLE ADVERSE ENVIRONMEN- TAL EFFECTS The only major adverse environmental effect of the expanded project is the noise impact of site traffic on residential areas along Humboldt Avenue between 65th Avenue and I-94. However, existing noise conditions exceed the standards for external conditions and the proportion of the increase caused by buses is small. Re-routing of some bus traffic to mitigate this effect is discussed in the report. Other minor, unavoidable, adverse impacts include increases in traffic volumes and localized air contaminant concentrations. The increase in traffic volumes generally will occur in the off-peak traffic periods of the day and will not result in any significant increases in congestion. The localized increases in CO emissions will not result in any violation of air quality standards. The proposed facility will result in an increase in demand on all utility services. However, this demand will not exceed the capacity of any of these services. 63 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, environmental analysis 5. SHORT-TERM USES OF MAN'S ENVIRON- MENT VERSUS LONG-TERM PRODUCTIV- ITY Minor adverse environmental conditions of short duration will be created during the construction of the facility. These include construction noise, dust, temporary erosion, unsightly debris, etc. All of these annoyances will end when the project is completed and can be minimized through measures previously discussed. The long-term impacts of the proposed project include localized increases in noise levels and air contaminants. These impacts will be mitigated _ over time through the implementation of air and noise pollution controls to the vehicles associated with the site. The project will require long- term commitment of resources such as money, land, building materials, and services. These commitments are necessary to attain the long-term improve- ments of mass transit service in the Minneapolis area. The improvement of mass transit service is anticipated to improve the environment through the more efficient use of energy (fuel) resources. 65 for a Q c a v c .. 0 a 3 w 0 m 0 c� M to W n M M W IV i m K c� A- Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, Inc environmental analysis for d Q c — cn a — c .. 6. IRREVERSIBLE AND IRRETRIEVABLE EN- o' VIRONMENTAL IMPACTS a 3 0 :. 6. CD There are no irreversible and irretrievable impacts or commitment of W resources other than the natural resource materials used in the actual 0 CD building construction and the energy resources (fuels) consumed in operat- 0 ing the buses and the maintenance facility itself (fuels consumed by theCD heating plant and in connection with electric and water services). All — resources used in the operation of the site (including land) have the N potential for retrieval and/or reversal at a later date. s 3 t� n 1 M 01 1 N M ti Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc _ environmental analysis for d Q c cn ch Cr c 0 w a 3 w c� APPENDIX A PERMITTED USES IN I-1 INDUSTRIAL CD PARK, BROOKLYN CENTER, MN s n W d 1 N J Section 35-330. I-1 INDUSTRIAL PARK I. Permitted Uses a. The following manufacturing activities: 1. Food and kindred products, as illustrated by: Dairy products Bakery products Confectionery and related products Beverages, with the exception of malt liquors Macaroni, spaghetti, and noodles 2. Apparel and other finished products made from fabrics, leather, and similar materials. 3. Lumber and wood products, except saw mills and planing mills producing dimensioned lumber. 4. Furniture and fixtures. _ 5. Converted paper and paperboard products (as opposed to paper and paperboard manufacturing). 6. Printing and publishing and allied industries. 7. Chemicals and allied products, as follows: Drugs Soaps, detergents, and cleaning preparations Perfumes, cosmetics, and other toilet preparations (compounding and packaging, only). 8. Miscellaneous plastic products. 9. Fabricated metal products, as illustrated by: Office computing and accounting machines Household appliances Electrical lighting and wiring equipment Communication equipment, including radio and television receiving sets Electronic components and accessories Screw machine products 10. Professional, scientific, electronic, and controlling instruments, photographic and optical goods, watches, and ^ clocks. 70 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc environmental analysis for d 11. Miscellaneous manufacturing such as jewelry and silverware, Q N musical instruments and parts, toys, amusement, sporting a and athletic goods and pens, pencils and other office and C artistic material. Cr c b. The following wholesale trade activities: 1. Automotive equipment CI 2. Drugs, chemicals and allied products w 3. Dry goods and apparel I+ a� _. 4. Groceries and related products m 5. Electrical goods n "- 6. Hardware, plumbing, heating equipment, and supplies c� N 7. Machinery, equipment and supplies 8. Other wholesale trade similar in nature to the aforementioned W uses, such as paper and paper products, furniture and home furnishings, and beer, wine and distilled alcoholic beverages, but expressly excluding petroleum bulk stations and scrap and waste materials and similar uses. c. The following service activities: 1. Laundrying, dry cleaning and dyeing N 2. Contract construction 3. Kennels 4. Veterinarian and animal hospitals 5. Automobile and truck rental and leasing d. Public transportation terminals (excluding truck terminals). e. Accessory uses incidental to the foregoing principal uses when located on the same property with the use to which it is accessory. Such accessory uses to include without being restricted to the following: 1. Off-street parking and off-street loading 2. Signs, as permitted in the Brooklyn Center Sign Ordinance 3. Storage of raw materials, work in process and inventory, provided such storage is within completely enclosed buildings 71 f. Other uses similar in nature to the aforementioned uses, as determined by the City Council. r- --A 72 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc _ environmental analysis ford Q c c 0 w 7-3 APPENDIX B _ SHINGLE CREEK ANALYSIS, A REPORT PREPARED FOR THE CITY OF BROOKLYN �. CENTER BY BRAUER ASSOCIATES cn n M 1 � c� t d K N .- ft- 73 i CONCLUSIONS SECTION In the past, the shaping of cities was determined by industry, railroads and highways. Cities today are undergoing a change in the development and physical character process. Attitudes toward nature and open space are becoming the dominant forces in urban shaping. -- Shingle Creek is a prime example of how an attitude can become a reality. Hard line construction drawings in this case may not be the answer to the subtleties of a quality experience that could result from continued involvement. The Park Commission, City Council and Planning Commission can promote this continued involvement. It is at this level that the decisions and administration of a program are accomplished. 1. The Shingle Creek Green Belt is a very real asset to the open space system in the City. It is a unique natural experience located within an urban space which for the most part has not been irreparably disturbed by man-made intrusions. It does, however, have certain limitations in terms of open space development due to its narrow width. It is recommended that the Green Belt be left in a natural state and supplemented with additional tree plantings. These plantings will create spaces for nature interpretation. The pedestrian and bicycle trail systems should be separated from each other and removed from the immediate edge of the creek bank. It should be provided with a surface treatment of wood chips (pedestrian) and bituminous asphalt (bicycle). 2. Motorized vehicles, including snowmobiles and trail bikes, should be prohibited from use of the trail system due to safety hazards to pedestrians and bicyclists. In addition, it can be anticipated that there would be certain damage to plant and animal life within such a narrow corridor. 3. Urbanization and continued industrial development along the Green Belt will undoubtedly increase at an accelerating rate. The implication of this development on adjacent land -uses, 74 Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc ironmental analysis for d Q c Cn could markedly affect the potential quality experience of the creek and Green Belt. In this context, areas of concern are related to water runoff and physical and visual intrusions: a. It can be anticipated that when full commercial and industrial development occurs along the Green Belt, there will be substantial water runoff introduced into Shingle Creek from parking lots and other hard cover surfaces. This runoff, coupled with natural drainage ways and percolation, may increase the possibility of damage to the Green Belt from creek inundation. While this report does not intend to provide an engineering analysis, it should be noted that a series of ponding areas with controlled outlets should be considered. It is suggested that such ponds, constructed in the vicinity of the creek could serve a dual purpose as a water reservoir and wild life habitat. b. Physical and visual intrusion created by the location of commercial and industrial development adjacent to the Green Belt should be minimized. Such structures, particularly industrial buildings, are constructed for function and are not generally endowed with special aesthetic qualities. Recognizing that the Green Belt must co -exist with such development, consideration should be given to a policy that would require variated setbacks of building structures and parking areas from open space lands. Such setback areas should be landscaped in a manner to provide visual relief, but not necessarily a barrier. It is felt that the policy should not be rigid in terms of requiring X number of feet for setback and landscaping, but rather it should be one which encourages sensitive design *.- and compatibility with adjacent open spaces. 4. Additional plantings around the Civic Center will continue the natural atmosphere of Shingle Creek into this area. The plant- ings will act as a visual and noise buffer to the Interstate, as well. 5. Shingle Creek is a delicate balance of nature. When the adjacent land is developed, it will be imperative to maintain the native plant element for erosion control. If the vegeta- tional habitat is destroyed, the existing creek banks will erode with the additional water runoff from development. .^ 6. The water -carrying capacity of the creek is controlled by a weir. The weir presently maintains the creek level within a -- 75 a Cr c 0 M D a 3 cv 5' CD D 0) D 0 cu n CD I - CD to N n M M X, d Xr d K o) M 6-inch constant. With development, the storm runoff coupled with loss of peat absorption, will increase the need to maintain the existing ecological balance along the creek. The re-routing of the creek to the west in the vicinity of the Civic Center will in no way jeopardize the flow capacity of the creek. 7. Present wildlife patterns need not be altered or destroyed. Wildlife can be maintained within any given locale, if the "critters" and their habitat are respected by man. The people of Brooklyn Center can do this at Shingle Creek by encouraging a natural trail system and additional planting, plus protection of the natural elements, i.e., strategically placed inlets and lagoons for wildlife habitat and introduction of native floodplain vegetation. 8. The proposed trail system for Shingle Creek should provide a varied experience. Undulations in the trail, both vertically and horizontally, can be achieved through earth sculpture and plant materials. A subtle structuring of the trail system will constantly open vistas while creating enclosed spaces affording a maximum variety of intrinsic experiences. Bicycle and foot trails should be separated as much as possible. Varied routes should afford a maximum alternative experience. 9. The trail will be included in the proposed Hennepin County Trail System. Principles of the Shingle Creek trail system must not be negated by the Hennepin County Trail System. 10. If the desired natural environment is to be effective, the trail and design development must establish the same theme. This can be achieved through the use of warm natural materials. The use of wood members in benches, light standards, waste receptacles, bike racks, etc., will do much to enhance and reinforce the intimate potential of Shingle Creek. Wood fiber or wood chips for the pedestrian path would impart this warm feel. The bicycle path should be stone or asphalt to accommodate rubber -tired vehicles. Carrying the theme further, the two paths could be separated by wood timbers (bollards) in groups of 3 to 5. In connection with the total effect, planting should be done with native vegetation, i.e., prairie grasses, cottonwoods, sumac, and cherry. 11. It is important to continue now with design development and the use of consulting services. At this time, these are the ideas and attitudes, but in order to be implemented, they must be directed. The intrinsic potential that exists should be implemented in development to achieve a harmony of natural and man-made elements through development of a trails system. 76 r Prepared for the Metropolitan Transit Commission by Barton-Aschman Associates, environmental analysis for v c cn cn 0 a� a w ,APPENDIX C AIR QUALITY METHODOLOGY CD 0 CD 0 1 M W V C1 c� C N :-i DETERMINATION OF MAXIMUM BACKGROUND CO CONCENTRATION In order to properly assess the impact of traffic on nearby ambient CO concentrations, it is necessary to include the background CO concentra- tions. Background CO concentrations are a result of general urban vehi- cular activity in and around the project site and not in the immediate vicinity of the receptor being analyzed. Of the air quality monitoring stations operated by the MPCA, the Midway Site (No. 360) was determined to be the most representative of back- ground levels in the Minneapolis -St. Paul metropolitan area. The Midway Monitoring Site is located along the 3400 block of University Avenue S.E. It is approximately 30 meters north of University Avenue and 6 meters east of Bedford Street. There are several local sources which exert an influence on CO levels recorded at the site: vehicle — movement in and around the nearby KSTP Radio Station parking lot, several local trucking operations, and the traffic along University Avenue. A good representative monitoring site for background would be at least 100 meters away from the type of influences delineated above. The most significant localized influence on the CO levels recorded at the Midway Site can be attributed to the traffic along University Avenue. Thus, the University Avenue contribution was subtracted from the peak CO level recorded at the Midway station in 1974. The localized impact of the KSTP parking lot activities and the nearby trucking operation were not dealt with, so their impact remains in an estimated CO background level. The 1974 annual average daily traffic (AADT) for University Avenue at the Minneapolis city limits, obtained from the City of Minneapolis, was 18,200 vehicles per day. In order to obtain peak 1-hour (V ) and 8-hour N) volumes, Appendix A of the U. S. EPA Guidelines for thl Review of In Sources was used. The appropriate equations are: V1 = AADT Seasonal Adjustment (0.094) Demand Factor - 1 HR V8 = AADT Seasonal Adjustment (0.5) Demand Factor - 8 HR ^ Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc environmental analysis ford v c N The constants 0.094 and 0.5 reflect the ratio of the peak 1 and 8-hour a demand, respectively, to peak seasonal daily demand. The Seasonal -- Adjustment Demand Factors for an urban arterial with an AADT of less than C 20,000 are 1.70 for the 1-hour peak and 1.4 for the 8-hour peak. - 0 Thus: V1 = (18,200) (1.70) (0.094) = 2,910 vehicles per hour and, a V8 = (18,200) (1.40) (0.5) = 12,740 vehicles per 8 hours or = 1,590 vehicles per hour W. 5 The next step is to convert the traffic data to CO concentration impacts CD at the monitoring station.. This was done using the Guidelines for the D assessment of CO impact from a traffic lane on a major street. The CD impact analysis is detailed in Table C-1. 0 �. The resulting 1-hour peak concentration must be corrected for the 1975 emission factor data used in the analysis. The resulting peak 1-hour y concentration attributed to the traffic along University Avenue is ? 9.84 x 1.1 = 10.8 ppm. ca c� The maximum 1-hour concentration must be converted to the maximum 8-hour 0 concentration. This is accomplished by multiplying the 1-hour concen- tration by the ratio of the average hour of the peak 8-hour volume to W the peak 1-hour volume and a meteorological persistence factor of 0.6. T The resulting CO impact of University Avenue traffic for an 8-hour average is: 10.8 X 115900 X 0.6 = 3.5 ppm. on 2910 In 1974, the maximum recorded CO concentration for an 8-hour average was 7.3 parts per million. The background concentration is simply computed by subtracting the CO impact from University Avenue from the maximum recorded value at the Midway monitoring station. Maximum CO background for 8-hour average in 1974 = 7.3 - 3.5 = 3.8 ppm. The maximum 1-hour background concentration is computed by dividing the 8-hour concentration by the meteorological persistence factor and multi- plying by the ratio of peak 1-hour traffic volume to the average hour of the peak 8-hour volume. 1974 peak 1-hour background CO = X 299110 = 11.6 ppm. T3.88 79 The 1974 peak 1-hour background CO must be converted to 1976 and 1980 background levels. This is accomplished by utilizing average emission factors.l 1976 peak 1-hour background CO = 11.6 ppm (1976 Emission Factor) (1974 Emission Factor = 11.6 �456 = 9.3 ppm 1980 peak 1-hour background CO = 11.6 ppm (1980 Emission Factor) (1974 Emission actor = 11 .6 (� _ = 4.8 ppm Table C-1 UNIVERSITY AVENUE IMPACT ON CO CONCENTRATIONS RECORDED AT MIDWAY MONITOR Lane Capacity Peak 1-Hr. CO Impactl Distance From Relative CO Impact Designation LS-E Volume V/C @ 10 meters Lane to Receptor Concentration Per Lane (meters) L-I 1000 728 0.73 4.8 33 0.57 2.74 L-2 1000 728 0.73 4.8 37 0.53 2.54 L-3 1000 728 0.73 4.8 41 0.49 2.35 L-4 1000 728 0.73 4.8 45 0.46 2.21 TOTAL 9.84 lObtained using USEPA Guideline, Figure 3. 20btained using USEPA Guideline, Figure 5. lCom ilation of Air Pollutant Emission Factors, Supplement No. 2, Second Edition), USEPA, September, 1973. -N Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc environmental analysis for d v cn ch cr 0 a w APPENDIX D CALCULATING AMBIENT NOISE LEVELS CD n CD CD 1 d 1 d N M Field measurements of existing noise levels were made utilizing a Tracor Recording Sound Level Meter, Model SPL 110B (Type II Meter, SN #118) with a remote electret capacitor type microphone having an omni-directional response. The meter stores the observed noise levels by a dotted trace (4 dots/sec.) on an integral chart recorder. The meter was calibrated in the field before and after each usage by a Tracor Model SPC-14 sound level calibrator (SN #533) according to manufacturer specifications. All field measurements were made according to ANSI standard field survey methods on "A" weighting scale and slow response. The microphone with windscreen was placed on a tripod approximately 5 feet above ground level. Wind speed, temperature, barometric pressure, and relative humidity were also monitored. The recorded noise levels were reduced manually to obtain the time distribution of noise. The calculation of both ambient and projected noise levels was made using the method, as outlined in National Cooperative Highway Research Program Report Number 117 (NCHRP 117), titled, "Highway Noise, A Design Guide for Highway Engineers", and NCHRP Report Number 144 (NCHRP 144), titled, "Highway Noise, A Field Evaluation of Traffic Noise Reduction Measures". The Kentucky Prediction Procedure Correction Factor was utilized to adjust the predicted noise levels for the low volume flow conditions, where applicable. This method utilizes the traffic volumes (truck and auto), traffic speeds and topographic features to predict noise levels. The existing and site traffic volumes utilized in the calculations were taken from the traffic evaluation study performed for the site. m Prepared for the Metropolitan Transit Commission by Barton -Aschman Associates, Inc