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HomeMy WebLinkAbout2.c. Storm Water IssuesCITY OF ROSEMOUNT EXECUTIVE SUMMARY FOR DISCUSSION COMMITTEE OF THE WHOLE OCTOBER 11, 2000 AGENDA ITEM: STORM WATER ISSUES AGENDA NO. DISCUSSION PREPARED BY: THOMAS D. BURT, CITY ADMINISTRATOR 2. C. ATTACHMENTS: UTILITY COMMISSION STAFF REPORT This information was presented to the Utility Commission on Monday, September 11 2000. Our engineeing consultant will be available for discussion and he asks for Council direction. - 8441 Wayzata Boulevard, Suite 350 B.A. Mitteweadt, P.E. Minneapolis, MN 55426, B ret Wi R w eirs, P.E. WSB Peter R Willenbring, P.E. Donald W. stun, P.E. �- tel: 763- 541 -4800 Ronald B. Bray, P.E. & Associates, Inc. fax: 763- 541 -1700 September 8, 2000 Rosemount Utility Commission City of Rosemount 2875 145d` Street West Rosemount, MN 55068 -4997 Re: Stormwater Management Issues /Concerns/Problems Within the City of Rosemount WSB Project No. 1005 -140 Dear Utility Commission Members: This letter and supportive documentation has been prepared to assist the City in properly responding to the flooding problems that occurred within the City of Rosemount following an extremely heavy rainfall event that occurred on July 7 and P, 2000. This event, which deposited up to eight inches of rain in three to five hours was classified as an event that exceeded a 1 chance of occurrence in any given year. This has also been referred to as an event that exceeded the intensity of a 100 -year storm. Additional information on this event is included in Attachment A. As a result of this rainfall event, many depressions, ponds, street areas, some septic systems, and a few homes were flooded. Most of the areas that were impacted were located in larger depressional areas that currently have no means for discharging water from these depressions except through evaporation or seepage. As a result of this event, a call for a more rapid implementation of the City's stormwater management plan was brought forth by many of the City's residents. Furthermore, some questions have arisen concerning whether the current stormwater plan is adequate to address other anticipated impacts such as those associated with flooding mature trees adjacent to these depressions during major events. Outlined below, please find a more detailed description of the location and flooding problems experienced in the identified problem areas. A map showing the location of these areas is also included as Attachment C. 1. Hawkins Pond - Hawkins Pond is a landlocked basin surrounded by residential homes located just north of 145th Street and west of Shannon Parkway. This pond was developed with a clay -lined bottom, thereby m aximizi ng the aesthetic features of the pond and minimizing the ability to allow stormwater to infiltrate. This pond was intended to be controlled through the installation of a lift station and forcemain outlet. The forcemain is installed within the subdivision, however, still needs to be connected between the subdivision and Diamond Path. The forcemain was recently installed along Diamond Path as a part of the Birger Pond storm sewer lift station. This project was anticipated to be completed in 2003, and $200,000 was allocated for the construction activity. Additional information will be handed out and reviewed with you at the September 11 2000 meeting. M inneapolis_ - St. Cloud Infrastructure Engineers Planners F: , %-P%%cttErrnmwrmosoo- fl..di+B.v+Pd EQUAL OPPORTUNITY EMPLOYER A Rosemount Utility Commission Rosemount, MN September 8, 2000 Page 2 2. Marcotte Pond - This pond has been named after the property owner located adjacent to the pond. The pond is located west of Shannon Parkway, just north of the new Evermoor subdivision. This pond is a landlocked depression that receives water from properties current under development on the west and east sides of Shannon Parkway. Prior to the July 7' rainfall, flooding in the depression had not been a significant issue. According to the adjacent property owner, a number.of years ago, a storm sewer from the east side of Shannon Parkway was sand- bagged to block flow from this area, or the pond could have been at or above the projected high water level. This pond has been studied in detail and a number of alternatives have been identified to address this problem. Flooding of trees has also been identified as a significant concern. Attachment B provides information related to tree flooding. This pond was not specifically identified in the CIP for construction, however, $250,000 was allocated for the Kelly Trust trunk in the years 2001 through 2003. Additional information will be reviewed with you at the September 11`x, 2000 meeting. 3. Keegan Lake - Keegan Lake is located north of County Road (CR) 38 and east of Trunk Highway (TH) 3 and has no defined outlet. The outlet for this pond is intended to be extended north and east through the current undeveloped property, ultimately discharging into the Uof N4 property. $500,000 was identified for this outlet to be constructed in the year 2003. Construction of this outlet is somewhat premature, considering that it was anticipated to be extended through a property that is yet undeveloped. However, other alternatives can be explored to address this issue in the near term. Additional information will be handed out at the September 11 2000 meeting. 4. Arland Evanson Property -Arland Evanson lives north of CR 38 just west of Keegan Lake on 132nd Court. Mr. Evanson has a garage that sits on the low side of his property and has a small ponding area that receives storm water discharged from his neighborhood area, as well as water that is directed to it from the south side of CR 38 and the Broadway complex. Mr. Evanson's drainfield was under water during the storm and his garage was flooded. This issue is somewhat related to the Keegan Lake situation, since this water would typically be directed into Keegan Lake. Additional information on the problem area will be handed out at the September 11'x, 2000 meeting. 5. Scott Selic -.'&. Selic has a situation similar to Mr. Evanson. His property is next to a ponding area adjacent to CR 38, just west of Shannon Parkway. This area receives storm water from the Oakridge Estate area and does not have a positive outlet. Mr. Selic's drainfield is also located in the low area that is easily flooded, thereby creating not only a health hazard, but an unusable septic system. We have instructed Mr. Selic to relocate his septic system to higher ground. Additional information on the problem area will be handed out at the September 11 2000 meeting. Rosemount Utility Commission Rosemount, MN September 8, 2000 Page 3 Recommended Approach/Process for Addressing Flooding Problems; In order for the City to properly respond to the flooding problems experienced above, it is recommended that the City take the following approach: 1. Review the policies and design standards that were utilized to develop the City's Comprehensive Stormwater Management Plan and define whether or not these standards currently are adequate to meet the City's needs. • As part of this effort, alternatives would be presented to the City Council in regard to providing various levels of water quantity management, quality management, funding, and in general, how you may want to design stormwater storage and conveyance systems, maintain these systems, provide related concerns. 2. Review City's Trunk Drainage System Layout. • As part of this task, the City's trunk system layout would be reviewed and discussed for the 3. 4. purpose of assuring we are meeting, the goals and policies of the City, as well as meeting the needs of downstream communities in accepting water from these areas. Trade -offs will also be discussed with the Council concerning the benefits and impacts associated with increasing discharge rates, decreasing discharge rates, acquiring stormwater storage areas, purchasing property and/or low homes as opposed to building improvements to protect existing structures, defining perceived City values regarding loss of vegetation around ponding systems, and other related issues. Review/Refine/Redefine City's Stormwater Trunk System Layout and Design Standards. • The task will compile current City perspectives outlined above. Provide detailed review and analysis of each of the problem areas and develop proposed solutions based on updated City policies and perspectives concerning stormwater management. • Some of this information will be available at the September 11' meeting, but additional follow -up will be necessary. 5. Develop implementation plan for stormwater management improvements. • As part of this task, it is anticipated a short-term and long -term implementation plan would be developed. The short-term plan will include the identification of capital improvement projects, as well as further define and support City policies and perspectives regarding short F wpd r ' ' Rosemount Utility Commission Rosemount, MN September 8, 2000 Page 4 and long -term water - related impacts. The long -term implementation plan will also be developed. Much of the information that has been identified to be developed in the above paragraphs has been, in part, developed as part of our initial review of these problem areas. Specific recommendations concerning how to address problems within these areas cannot be finalized until the City has an opportunity to review and rethink some of the design standards and policies that have been utilized in the past. At the meeting on Monday, September 11 we will provide you with additional information on each of the problem areas identified, as well as describe potential alternatives for corrective actions. Sincerely, WSB & Associates, Ins Peter R. Willenbring, P.E. Bret A. Weiss, P.E. Vice President President rim H 8oadin &wPd FEIN A-rwcvkfveor Pr Torrential Rains Douse South Metro July 7 -10, 2000 Torrential Rains Douse South Metro July 7 -10, 2000 Torrential rains fell upon the Twin Cities Rainfall Totals metropolitan area during the weekend of July 7 10. The spate of severe weather began during the morning of Friday, July 7 when severe storms rumbled through the east metro. High winds, hail, and possible tornadoes led to significant property damage. The south metro, specifically the city of Eagan, received an extraordinary amount of precipitation later on the 7th and during the early morning hours of Saturday, July 8. Over eight inches of rain fell in a three to five hour span across a small area of northern Dakota county. The climatological probability of receiving eight inches of rain in a five hour period for a given location in the metropolitan area, in a given year, is far less than Pagel of 2 _= 9 s: 7 6 3 4 3 2 � Inches 1 %. Prepared by. State CCatrato logy Office. ONR• Waters Data provided by. Dakota Sod and Water Conservation District Metropolitan Mosquito Control District An additional two to three inches of rain drenched National Weather s ervic e already sodden neighborhoods during the evening of July 8 and the early morning of Sunday, July 9. Light rainfall fell again late in the late evening of July 9 and the early morning hours of Monday, July 10. The highest reported weekend rainfall total was 11.33 inches in southeastern Eagan. The heavy rains led to extensive damage in some south metro communities. Serious urban flooding was commonplace, and severe erosion was reported m many areas. One life was lost in a flood- related incident. WSI radar based precipitation estimate July 8 WSI radar based precipitation estimate - July 9 WSI radar -based precipitation estimate -July 10 (revised 7 /11 /00) Return to the Climate Journal mcw Q, o113.uznn.cd,r URL: http- J/climste umn e d u /d o di curn al/flash_ffoodstOW10 m Lan modified: July 11. 2000 711'7 PRECIPITATION ( INCHES) FIGURE _ 1 GRAPH OF PRECIPITATION VS. TIME FOR MAJOR RAINFALL EVENTS RP 7/23- 24/87 INFALL. EVENT 4, 9130/17 ' ,° 'RAIN ALL E, f:NT • 45 TIME 4 (HRS.) I le O 0 2 4 6 8 10 PRECIPITATION ( INCHES) TABLE 2 RAINFALL IN HNNEAPOLIS -ST. PAUL METROPOLITAN AREA FOR DURATIONS FROM 30 MINUTES TO 24 HOURS AND CHANCES OF OCCURRENCE PER YEAR RANGING -FROM 1% TO 99% Data Taken from U.S. Department of Commerce - Weather Bureau Technical Paper No. 40 - Dated May; 1961 Chance of 24 -Hour 12 -Hour 6 -Hour 3 -Hour 2 -Hour 1 -Hour 30 Minu tes Occurrence _99+ 2.3 2.0 1.7 1.5 1.4 1.2 0.9 50% 2.8 2.4 2.1 1.9- 1.7 1.4 1.1 20 3.6 3.1 2.7 2.3 2.2 1.8 1.4 10% 4.2 3.7 3.1 2.6 2.5 2.1 1.7 4% 4.6 4.2 3.5 3.0 2.8 2.3 .1.9 2 % 5.3 4.6 4.0 3.4. 3.1 2.7 2.1 1% 5.9 5.0 4.4 3.8 3.5 2:9 2.4� City of A Anthony Page 9 WSB Project No. 1065.11 BA Mmdmmd r, P.E. 350 Westwood Lake Office Bret A Weiss, RE - 8441 Wayzata Boulevard Peter R. Willenbting. P.E. Minneapolis, MN 55426 Donald W. sterna, EE Ronald B. Bray, EE. - -- 612- 541 -4800 & Associates, Inn% FAX 541 -1700 Memorandum To: Bret Weiss Pete Wdknbring From: _ Andi Moffatt Date: August 24, 2000 Re: Affect offlooding on oak trees As requested, I have investigated the flooding tolerance of bur oak and swamp white-oak. These two species were determined to be the trees present near the pond in Rosemount based on leaves collected by Bret. The following sources were consulted to detennine the general flooding tolerance of the oaks: • National Audobon Society Field Guide to North American Trees • MnDOT Plan Matrix CD-ROM • Minnesota Plant List that Occur in wetlands • Flooding and Its Effects on Tres • Professional opinions from Jeff Lutz and Tom Moffatt While oaks in general are generally intolerant of flooding, based on the information gathered, both species at the site are somewhat tolerant of flooding. Information from the document Flooding and Its Effect on Trees ( attached) indicates that swamp white oak and 'bur oak are able to survive flooding or saturated soils for 30 consecutive days within the growing season. With that said, this type of continuous. stress on the tree year after year could eventually lead to its decline and death. If flooding occurred in the late winter when the trees were dormant, it is anticipated that the negative impact of flooding would be signif cantly reduced since 1) the trees would not as actively be transporting materials through the vascular system as they do during the growing season, and 2) the soil would rely not reach anaerobic conditions since soil microbes are not as active -in cold temperatures. Many other factors play a role in a tree's susceptibility to being impacted by flooding such as species variation, general health and age of the tree, and water movement, etc. Therefore, while it cannot be determined for certain, it is anticipated that these trees could withstand 30 consecutive days of flooding provided that this type of stress did not occur annually and/or occurred when the trees were dormant. It is anticipated that less prolonged flooding (1 -2 weeks) would have less of an impact if it occurred on an annual basis. If you have any questions, please let me. know. Minneapolis St. Cloud Infrastructure Engineers Planners FLOODRSTG and its effects Trees, Flood Tolerance of Trees � Page 1 of 6 - 7 _ Flood Tolerance* of Frees Numerous studies have been conducted to help foresters and natural resource managers understand the impact of flooding on trees (see bibliography). The state -of -the -art, however, has not developed sufficiently td warrant a- precise statement on the adaptability of a species to a specific flooding situation. Conclusions from different studies are often contradictory, caused in part by the physiological responses of the tree as it interacts with environmental conditions. Since these environmental conditions are not well understood, as well as the difficulty in catego tree species over their entire range, flood tolerance predictions must be carefully evaluated in general terms. A brief review of soil, tree, and flood characteristics indicates the complexity of these interactions. soils The following soil- related points are important in understanding flooding effects on trees. Soil Aeration Flooding results in poor soil aeration because the supply of oxygen to flooded soil is severely limited. Oxygen deficiency is likely the most important environmental factor *.hat triggers growth inhibition and injury in flooded plants. - PH Flooding of soil increases the pH of acid soils and decreases the pH of alkaline soils. Organic Matter The rate of decomposition of organic matter in flooded soil tends to be only half that in an unflooded soil. The major end products of decomposition of organic matter in flooded soils are carbon dioxide, methane, and humic materials. In addition, high concentrations of ethanol and hydrogen sulfide are produced in waterlogged soils which can be damaging to root systems. Sedimentation Deposits of silt or sand as shallow as three inches may seal over and smother tree roots by limiting the supply of oxygen. Species vary in tolerance to sedimentation, but all seedlings are susceptible to root injury. Eastern cottonwood, baldcypress, tupelo, and black willow seedlings can withstand moderate station. Scouring Strong currents, waves, or suspended particulates may cause soil around the base _ of the tree to be washed away, exposing tree roots. Exposed roots can lead to not http: //willow.ncfes.i mn.edu/Flood/toler.htm 08/17/2000 FLOODING and is effects Trees, Mood Tolerance of 'Frees Wage 2 of b only tree stress but can make the tree more vulnerable to windthrow. Trees Various characteristics of a tree affect its flood tolerance with the most prominent presented below. - Height Tree in ury increases in proportion to the percent of crown covered by water. Species that can survive standing in several feet of water for months may die in less 'than one month when their foliage is completely covered. Few species can tolerate more than one month of complete submersion during the growing season Crown Class Trees in the dominant crown class survive flooding much better than trees in lower crown classes. Age ,A-&h trees tolerate flooding better than overmature trees or seedlings of the same species. Therefore, some species rated as flood tolerant may quite sensitive in the seedling stage. Seedlings often die because they are pushed over, buried in mead, or uprooted. Vigor Tree vigor at time of flooding influences tolerance. Vigorously growing, healthy trees withstand flooding better than less vigorous trees. Tree vigor may be irrelevant, however, if the tree is totally submersed in water. Roots Long -term flooding leads to death and decay of large portions of a tree's root system (see section on Management implications for windthrow problems). During flooding, some species can maintain normal roots in an active or dormant condition, others rely upon new secondary and adventitious roots tha rmay form from the root collar or on the trunk near the water surface. Species unable to either maintain normal roots or grow new ones can qulcldy die. Species Variations Flood tolerance variations within a species are not well understood. Mood tolerance may be an inherited trait and this may explain some of the discrepancies in reports on surruvival. (Research methodologies also may vary from one study to another, - ccntnbuting to contradictory conclusions). However, it is generally accepted that some species have greater tolerance for flooding. than others (see Tables 1, 2, and 3). Floods Determining flood tolerance is complicated by the diverse characteristics of floods. Season httpJ flow .ncfes.;mm.edu /1~loodltoler.htm 08/17/2400 FLoODING and its effects Trees, Mood Tolerance of Trees Wage 3 of S Flooding during the growing season usually is more harmful to woody plants than flooding during the dormant season. Specifically, trees are most susceptible to flooding in late spring just after the first flush of growth. The tithing of a spring flood influences species differentiation. For example, since silver maple flushes earlier than green ash, an early flood might be more damaging to silver maple while a later flood more injurious to green ash Duration The longer trees are exposed to flooding, the greater the potential for fury. Most trees can withstand only 14 months with water being continuously over the soil surface. Short periods of flooding during the growing season can be tolerated by most trees. However, if flooding is recurrent and keeps the sod saturated or prevents recovery from previous flooding, injuries will accumulate and serious damage may occur. Water Level The depth of water influences flood tolerance. The mortality rate is less for trees in saturated soils than for trees with water covering the soil. Alter water covers the soil, the depth may have little significance until the lower foliage is covered; research results, however, differ on this point. Tolerance to complete submersion is much lower than tolerance to shallower depths of water. Temperature said Oxygen Cold water is less injurious than warm dater due to cold water's capacity to hold more dissolved oxygen. Rapidly flowing water (with higher oxygen content) is less harmful than stagnant water. Mechanical uajuries An often overlooked aspect of flood damage is mechanical injury caused by cur - rent, wave action, and floating debris. Young tree plantings may be especially damaged by current and wave action. Floating debris can injure both small and large trees. Chemicals Floods may carry various chemicals that have been pit up as runoff from agricultural fields and other areas or from sewage released why treatment facilities become unable to handle large volumes of water. The impact depends upon the type and dosage of chemicals. Tolerance Categories Tables and Table 1 present a summary of the research pertirtent to flood-tolerant trees and shrubs for three geographical divisions (districts) of the U.S. Army Corps of Engineers: Lower Mssimippi Valley, Missouri River, and North Central (see Figure 1). These three divisions include a majority of the foresdand flooded during 1993. http:// willow .ncfes.umn.edu /Flood/toler.htm 08AV2000 F..... OODLNG and its effects Trees, flood Tolerance of Trees Page 4 of 6 Smith e� Loaner 1 �1') 4 WssiSSOP Val Table ? combines research results from the Lower Nssissippi Valley and the Missouri River divisions. Since classification is relative, flood tolerances are best viewed as overlapping from one tolerance category to the next. Where research results differed between Lower Mississippi Valley and Missouri River studies, species are classified into two tolerance categories. The tolerance categories in Table I should be interpreted as follows: Very Able to survive deep, prolonged flooding for Tolerant more than one year. Tolerant Able to survive deep flooding for one growing season, with significant mortality occurring if flooding is repeated the following year. Somewhat Able to survive flooding or saturated soils for 34 T'oler'ant consecutive days during the growing season. intolerant Unable to survive more than a few days of flooding during the growing season wWx)ut significant mortality. Table 2_ which presents the results of an Illinois study, is the most comprehensive in the North Central Division. It is important to note that the flood tolerance categories in Table 2 differ from Table I in both name and definition. Table 2 tolerance categories should be interpreted as follows: http- //willow.ncfes.umiL edu/Flood/toler.htm 03/17/2000 FLOODING and its effects Trees, Flood Tolerance of Trees Page 5 of 6 Tolerant Most individuals survived more than 150 days of . flooding during the growing season Somewhat Some individuals killed by less than 90 days of Tolerant flooding and some individuals survived greater than 150 days of flooding. Slightly most individuals survived more than 50 days but Tolerant less than 100 days of flooding. intolerant Severe effects wah less than 50 days of flooding. Mg-ble 3 provides flood tolerance ratings for cultivated woody plants in New York subjected to a growing season flood- (June 1972). The species listed in Table 3 are commonly available in the landscape trade and are frequently used in park landscapes and urban settings in the Midwest and the Great Plains. Because Table 3 'is based on a short duration flood (10 days), information on the intolerant species (those killed or damaged) will be of the most use to practitioners. It should be noted that Tables 1 -3 classify tree and shrub species tolerance relative to continuous, rather than intermittent, flooding. Some species, for example, might tolerate one year of continuous inundation but only 3-4 months of intermittent flooding. Also, some sites affected by the 1993 floods in the Midwest and the Great Plains had soil . saturation up to 90 days prior to flooding. Consequently, the factors of soil saturation prior to flooding and continuous versus intermittent flooding must be considered when predicting the relative flood tolerance of species. With the exception of the tolerance ratings for haekberry, green ash, and shingle oak, Table 1 is more conservative in its tolerance ratings than Table 2. Table 1 includes more species than Table 2 and is based on a summary of studies from a broader geographical area. Consequently, Fable I is recommended as thefield guide " forBem and o &er resource managers who are evaluatdngflood aged #Tees in the MI'd vest and the Grew PWns. References Barry, P. 3., Anderson, R. L., and K M. Swain. Undated. [How to Evaluate and Manage Storm-Damaged Forest Areas.] Southeastern Area, U.S. Forest Service. 15 p. Bell, D. T., and E L. Johnson. 1974. [Flood -I aused Tree Mortality Around Illinois Reservoirs.] Trans. Ill. State Acad. Sci. Vol 67 (1): 28 -37. Broadfoot, W M.., and I3. L. Williston. 1973. [Flooding erects on Southern Forests.] Journal of Forestry. Vol 71(9): 584 -587. Hook D.D. 1984. [Waterlogging Tolerance of Lowland Tree Species of the South.] Southern Journal of Applied Forestry. Vol 8 (3): 136 -149. http:// wfilow .ncfes.umn.edu/Flood/toter.htm 08/17/2000 ;~LOODh G and its effects Tress, Florid Tolerance of Trees Page 6 of 6 KozlowsK T. T., Kramer, P. 7., and S. G. Pallardy. 1991. [Soil Aeration, Compac- tion, and Flooding.] in The Physiological Ecology of Woody Plants, New Mork: Harcourt Brace 3ovanovich. 303 -337. Loucks, W. L. 1987. [Flood- Tolerant Trees.] Journal of Forestry. loch: 36-40. Missouri Department of Conservation. 1993 (Summer). [The Effect of Flooding on Trees.] Missouri Forest Management Notes. Vol 5 (3): 1 -2. White, R_ M. 1973. [Plant Tolerance for Standing Water: An Assessment.] Cornell Plantations. Vol 28: 50-52. Whitlow, T. H., and R W. Harris. 1979. [Flood Tolerance in Plants: A State -of- -the - Art Review.] National Technical Information Service, U.S. Dept. of Commerce. August: 1- 161. Retain to the Tab €e 08/1772000 httpJ/ willow .ncfes.umnedu /F1oodholer.htm Flooding and its effects on trees, Table 1 ?arks a'd �r y a TABLE 1 Page 1 of 3 Marilyn LCWJ agwata Shagbark hickory X Robert Nethercut Mark M. ja tomentosa Mockermrt hickory X 01scLeltis IaMgata -� a tolerance of trees and shrubs to flooding during the growing season, SL Pard and er Mississippi Volley and Missouri Ri ver Divisions. Swamp lit' X ,Umsq Countp ounce: Whitlow and Farris 1979) Hackberry X Jerry Seck� Marsha Sotta?w occidentalis Comm Very ewhat 1621 Beechwood Ave. St. Paul, MN _lutes Name Tolerant! Tolerant= T Intoleraut 651 -698 -454 Downey hawthorn X Bluffs Project hl�3�a triacanthos MW fdenftfthe A gzwdo Boxelder X X President . Acer rubrwn Red maple X Ilex decidua Perry R. Bolin Vice Presidenticer saceliarinum Silver maple X X Jeanne W31} rugosa Hazel alder X Treasurer James R. ac er Directors Betula nigra River birch X Craig An Theresa Baa atica ' Water hickory X Dan Co ti Thomas Tdaj j l89rdiformis Bitternut hickory X Neil Franey William Fla illinoensis Pecan X X Elaine Jo son a lacfniosa Shellbark hickory Esther Re Marilyn LCWJ agwata Shagbark hickory X Robert Nethercut Mark M. ja tomentosa Mockermrt hickory X 01scLeltis IaMgata Sugmberry X Sco Swamp lit' X Pierre RegFi Ws occidentalis Hackberry X Jerry Seck� Marsha Sotta?w occidentalis Buttonbush X Vice President bNr£anadensis Redbud X Samuel H. Morgan Director Emeri&rn=.loner Flowering dogwood X David Lit! staegus mollis T W Downey hawthorn X roman rter Ex Officio Dennis AsbAWyros W?Vniana Persimmon X Thomas E um Marc Goess Greg MacicForesteria acuminata Swamp lit' X Terry Noo nus amencana White ash X Vic Wittgenstem. Executive Dired�rars permsylvanica green ash X X and Secretary Peggy Lynch Mississippi Riaeditma aquatics Waterlocust X Bluffs Project hl�3�a triacanthos Honeylocust X Cindy Schwie X Gymnocladus dfoicus Kentucky caff=tree Ilex decidua Deciduous holly X Ilex opaca Amencan holly . X http:// wiUow. ncfes .i,mn.edu/Flood/floodtblI.htm 08/17/2000 Flooding and its effects on trees, Table 1 z ?.Irks and r � � d o G to N ww' Black walnut w 1 \ �.. nigra ..�..� d 5% -T �r '' Page 2 of 3 X siyraeiflua Sweetgum X SG Paul and ,011111W Ramsev Cow ty s rubra Red mulberry X jVyssa aquatica 1621 Beechwood Ave. St. Paul, MN r 8 sylvadca Blackgam X 651- 698 -454 - wwwfriesdwfthe %hinata Shortleaf pine X President Pines We& Loblolly pine - X Peuy R. Bolin Vice President0lanera aquatica Waterelm X Jeanne Vei Treasurer at us occidentalis James 9ncier Sycamore X X R. Directors Populus deltoides Eastern cottonwood X Craig Andresen Theresa B+rPil li Ply X Dan Co . arofina Blau cherrY X Thomas Wight Neil Franey X William locus albs White oak Elaine Jollpson ' bicolor Swamp white oak X Esther K ��s Marilyn firlcata Southern red oak X h & Robert Ne ercut Mark M. ins imbricmia Shingle oak X Janet Olt _ereus l}rata R a'�P oak Scott ay Pierre RelAarcus macrocarpa Bur oak X Jerry S I ecir Marsha Sa marilandica Blaclgack oak X Vice President nigra Water oak X Samuel H. rgan Director Emeri@uercus nuttallii Nuttall oak X Truman David � s palustris Pia oak X Ex Officio Quercrus phellos Willow oak X Dennis Asmussen Thomas EYfcus rubra Red oak X Marc Goe ercus shumar&i Sh amard oak X Greg Mack' X Terry NocQwrcus stellata Post oak Vic Wittgenstein Executive Dire4ke?'w veludna Black oak X and Secretary Peggy L y� C i�'lix idgra Black willow X Mississippi River X Bluffs Project s albidum Sassafras Cindy Sch gi�,� .. Taxodium distfchum BaldOn=ss U nus alata Winged. elm X http:/l wMow. ncfes .umn.edu/Flood/floodtbll.him 08/17/2000 Flooding and its effects on trees, Table 1 Page 3 of 3 ?arks an �� N am ncana American elm X CIE ruhra Red elm X St. Pmd and °'O�.,r ery Tolerant: able to survive deep, prolonged flooding for more than 1 year. 2 Tolerant: able to survive deep flooding for one growing season, with significant mortality occurring if flooding is repeated the following year. 1621 Beechwood Uomewhat Tolerant: able to survive flooding or saturated sods for 30 consecutive days Sc Paul, MN 5511 during the growing season. 651- 698 -4543 %w hiendsottheparimo w �ntolerant: unable to survive more than a few days of flooding during the growing President season without significant mortality. Perry Vice Presiqftt Jeanne Weigum Treasurer James R. $richer Directors Craig Andresen Theresa Bradshaw Dan Collins Thomas T. Dwight Neil Franey William Frank Elaine Johnson Esther Kellogg Marilyn Lundberg Robert Nethercut Mark M. Nolan Janet Olson Scott Ramsay Pierre Regnier Jerry Seck Marsha Soucheray Vice President Emeritus Samuel H. Morgan Director Emeritus David Lilly Truman W. Porter Ex Officio Dennis Asmussen Thomas Eggum Marc Goess Greg Mack Terry Noonan Vic Wittgenstein ` Executive Director and Secretary Peggy Lynch Mississippi River Bluffs Project Manager > Cindy.Schwie http: //willow.ncfes.imm edu/Flood/floodtbllIfin 08/17/2000 Flooding and its effects and on trees, Table 2 Page 1 of 2 TABLE B Relative tolermce of Illinois t to flooding during the grog meson. (Source: Bell and Johnson 1974 ). NOTE: Flood tolerance categories in Table 2 differ from Table 1 in both name and definition. Somewhat SHOtly Species Common N=me Tolerant' Tolesant ToleranO Lxtolerant Acer negundo Bawider X .4c--r saccharimun Silver nL*e X Cwya ovata Sbagbarkhickwy X Carya tomentosa Mod=nutbidwry X Celds occidentalis Aadd)eny X Cercis canadends Reid X Crataegus mollis Downy hawthorn X Diospyros WiVniana ' Persimamn X Aglans nigra Black wahmit X Fraadn= pennsylvaWca Cheen ash X Gle&tda triacanthos Honeyloc= X Platxw ocddeata& Sy re X Populus deltoides F. 9= cottonwood X Prunes serotina Black sherry X Quercus alba White oak X Quercus bicolor Swamp white oak X Que=s impricaria Shingle oak X Quercus macrocarpa Bar oak X Quercus pahatds Pia oak X Quercus rubra Red oak X Quercus velutina Black oak X Salix nigra Bla& wfflaw X Sassafras albidum Sassaftas X http / hwfflow.ncfes.umn.edwTlotxl/flQOdt -htm 08/17/2000 Flooding and its effects and on trees, Fable 2 Page 2 of 2 Ulm= americma American elm X I Tolerant: most individuals survived more than 150 days of flooding during the growing season. 2 Somewhat Tolerant: some individuals killed by less than 90 days of flooding and some individuals survived greater than 150 days of flooding. 3 Slightly Tolerant: most individuals survived more than 50 days but less than 100 days of flooding. 4 Intolerant: severe effects with less thaw 50 days of flooding. Back http:// willow. ncfes.umn.edu /Flood/floodtbl21tra 08117/2000 Marcotte Pond Outlet Feasibility Analysis Rosemount, MN WSB Project No. 1275 -003 Prepared for: City of Rosemount September 2000 Prepared by WSB & Associates, Inc. 8441 Wayzata Boulevard, Suite 358 Minneapolis, MM 55426 Marcotte Pond Outlet FeasibOy Anabsfs City of Rosemount WSB Project No. 1275 -003 EW—S ZI bN PAV SSM moruasogJb 413 nsdpw4mvwj Ppno puod anounlll c aid L aAJqvU"nV J c aaQvd 9 aA.WW)tV 3 aaQnd s aA.WWIIV '.T t Abd y aA.4uu"nv Q € a-Qnd E u"nv F a-Qnd Z aA.Mu ";lip 'S Z a.Qnd I AW. WOIIV 'b' Z a-Qnd • • uualgo rd ayj ssaippV of a14b1?oAV SOA.VM nVfO malA U I a,Qvd .................... uralgo rdfo uoudzrasaa1 puno ng f uo.Wnpo4uj j s =ua;uogfo algn.L I. Introduction / Background /Description of Problem Marcotte Pond is located in the northwest comer of the City of Rosemount. It is generally located west of Shannon Parkway and north of the Evermoor Development. The pond encompasses an area of approximately four acres and is surrounded by mature oak trees. The City's Comprehensive Stormwater Management Plan anticipates the watershed tributary to Marcotte Pond encompasses an area of approximately 390 acres. It has an anticipated normal water elevation of 906.0, a high water elevation of 914.4, storage volume of 35.9 acre - feet, a proposed outlet of a 15 cfs lift station. The plan anticipates this water to be pumped to Birger Pond via a combination of a forcemain and gravity system. A survey of Marcotte Pond was completed in August of 2000 and identified mature oak trees present around the perimeter of the basin at an elevation of 908. Recent heavy rainfalls in Rosemount have raised the water elevation in this pond to close to the high water level. The property owner adjacent to this pond has significant concerns regarding the impact of these high water elevations on the mature oak trees in the area. Additional information is attached on the duration to which oak trees of this species can tolerate high water elevations. At the present time, no formal outlet is available for Marcotte Pond. Although the City's stormwater management plan identified a 15 cfs lift station to be constructed in the future to service the pond outlet, this lift station has not yet been constructed. Furthermore, based on the City's stormwater plan, even with this 15 cfs lift station installed, under fully - developed conditions, 100 -year high water elevations of 914.4 be anticipated. This is a very large lift station, however, it would still serve as a means to lower the pond from the HWL to the NWL following a rainfall event. It is also noted that an existing easement encompasses approximately 4.2 acres around the Marcotte Pond. A survey of the perimeter of the basin indicates that this easement was acquired to an elevation slightly lower 910.0. Utilization of the pond to the proposed 100 -year high water elevation of 914.4 would require additional easement acquisition. The City's Comprehensive Stormwater Management Plan proposed a lift station to be constructed at a cost of approximately $335,000. Generally speaking, the problems that have been identified with the Marcotte Pond include the following: Mamae Pond Outlet Feasibi o Analysis City of Rosemount WSB Project No. 1275: 003 Page I • Lack of an adequate drainage easement to accommodate high water elevations identified in the City's Comprehensive Stormwater Management Plan. • Concern by the property owner that allowing water elevations in the pond to reach planned levels will impact mature trees in the area. • The cost to construct a lift station having a capacity anticipated in the City's stormwater plan will be costly. • The property owner in the area has expressed grave concerns regarding an immediate need to provide an outlet and subsequent relief from high water elevations in this basin. H. Review of Alternatives Available to Address the Problem Based on a review of the information outlined above, we have identified a number of alternatives that could be considered to address the identified problems. Outlined below, please find a description of these alternatives, along with a listing of the advantages and disadvantages associated with each. A. Alternative 1 Construction improvements per the City's Comprehensive Stormwater Management Plan with additional construction of a berm along north and west easement line of Marcotte Pond to provide additional protection for trees and limit ponding within the identified easement. The City's stormwater management plan proposes to construct a 15 cfs lift station to carry water to Birger Pond under this scenario. 1. Advantages o f Provosed Improvement • Less surface area required for stormwater ponding. • Reduced tree and shoreline vegetation impact due to less frequent inundation. 15 cfs pumping capacity returns basin to normal water level within 3.4 days for the 100 -year, 24 -hour event. + Reduce costs for easements as impoundment would be limited to areas within berm.` Marcove Pond Outlet Feasibility Analysis Cky of Rosemount "B Project No. 12 75 003 Page 2 2. Disadvantages • Increased stormwater storage volumes upstream resulting in increased impacts for vegetation along shorelines and need for easements. • Increased maintenance would be necessary for two -stage outlet structures that would be incorporated into upstream impoundment projects. D. Alternative 4 Excavate Marcotte Pond to lower normal water level three feet and add six acre -feet of additional stormwater storage, reduce discharge to 6 cfs, restrict upstream discharge rates per previous discussion. 1. Advantages • Reduce lift station cost. • Improved infiltration and evaporation. • Reduced berm construction necessary. 2. Disadvantages • Excavation of Marcotte Pond may require wetland mitigation. • Water elevation fluctuations will be increased. • Additional costs associated with excavation. • Greater tree impact in upstream basins. E. Alternative 5 Construct 3 cfs lift station, construct larger basin, purchase expanded easement, and utilize upstream depressions for storage as necessary. 1. Advantages • Significantly reduced cost. • Less shoreline impacts in upstream basins. • Increased detention time in Marcotte Pond. • Reduced impacts on Birger Pond. Marcone Pond Outlet Feasibility Analysis City of Rosemount WSB Project Na 1275:003 Page 4 2. Disadvantages • Land acquisition costs. • Tree impacts for basin expansion. ' Loss of taxable property. F. Alternative 6 Utilize combination of permanent lift station and mobile diesel pumping station. 1. Advanta,�es • Diesel pump does not require electricity for operation. • Pump can be utilized at different locations throughout the City to pump landlocked basins or be utilized to further increase the capacity of the Marcotte Pond outlet. • Appears to be a cost- effective way to deal with more than one problem. 2. Disadvanta • Increased maintenance and labor intensive operation of diesel pump. • Increased noise. G Alternative 7 Utilize independent contractor to provide pumping equipment/pipmg and hoses as necessary to reduce water elevations in basins throughout the City. 1. Advantages • City would have reduced capital costs. • Additional City staff would not be required. • Depending on usage, this could reduce capital intensive improvements significantly. 2. Disadvantages • Additional noise • Likely would receive increased impacts to shoreline vegetation. • Last time, cost for pumping exceeded $200,000. Marroue Pond Outlet Feasibility Analysis City of Rosemount WSB Project Na 1275 -003 Page 5