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6-17-24 Speaker Forms & HandoutsCITY OF ATLANTIC BEACH L/ IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR T//O�� THE MEETING. ,p Date: Yf / Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: /Q Address: 7/�k �R/ r �� �`�, V �-- �A1�5 X2 - ca L g � %� 1. •C�wl Phone #: 3 Email: ©!i�% PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AlfZ� ITEM # OR SUBJECT TO BE DISCUS,$ED (DE$CRWE BELOW) COAB STORMWATER WORKSHOP Monday June 17, 2024, 6:00 PM Gregory Powell, PhD, PE Fo: Good evening! For the Record: 1. Name: Gregory Powell 2. Address: 1871 Selva Marina Drive, Atlantic Beach, FL. 32233 3. 1 have lived at this address for over 30 years. 4. BS(1972), ME(1975), Ph.D.(1980) in Engineering, from the University of Florida. 5. Licensed Professional Engineer in Florida since 1982 (PE No. 31165). 6. Worked for over 40 years as a consulting engineer specializing in Civil, Environmental and Water Resources Engineering. 7. 1 have testified as an expert in administrative hearings and in court over 15 times on subjects including: Hydraulics, Hydrology, Water Quality, Water Supply, Stormwater Management, and Wastewater Disposal. 8. 1 am now semi -retired, and I am here representing myself as a property owner in COAB. If time will allow, there are a number of issues with the current Chapter 24 stormwater regulations that are TECHNICALLY INCORRECT, and in my professional opinion, they are NEITHER REASONABLE nor APPROPRIATE. However, before I address those issues, I would like to start with three aspects of the Chapter 24 Stormwater Regulations that are foundational, and in my opinion are REASONABLE AND APPROPRIATE. 1. The OBJECTIVE of the Chapter 24 Regulations: a. As discussed in the Storm Water Master Plan, developed by CDM, as far back as 2012 (SWM P 2012), the objective of the stormwater regulations is to control EXCESS stormwater runoff from IMPERVIOUS surfaces. b. EXCESS runoff is the increased runoff from an IMPERVIOUS surface, when compared to runoff from a typical PERVIOUS area (SWMP, 2012). c. It's clear from the language of the code cited in this document that there shall be no increase in the rate or volume of flow from development or redevelopment of a lot. d. It is also clear from the history of development in Atlantic Beach, and other places, that unregulated development leads, overtime, to increases in the percent impervious area, which increases offsite stormwater runoff, which can lead to localized flooding. e. This OBJECTIVE is both REASONABLE AND APPROPRIATE. f. My concerns are not with the OBJECTIVE, but with the IMPLEMENTATION. 2. The DESIGN STORM EVENT required by Chapter 24. a. The design storm required is a 25 -year, 24-hour event with a rainfall depth of 9.3 inches. b. This design storm is commonly used in stormwater analysis and regulation. c. In my professional opinion it is REASONABLE AND APPROPRIATE. Page 1 of 5 COAB Stormwater Workshop 6/17/24 3. The DEFINITION OF IMPERVIOUS SURFACE (Section 24-17) a. The first sentence of this definition is CORRECT. b. An IMPERVIOUS SURFACE is a surface that prevents the entry of water into the soil. I will not be presenting any calculations today to support my conclusions. However, I have provided them, in the past to City staff and would be happy to provide them to others that wish to review them. Now, I would like to discuss my concerns with the Chapter 24 stormwater regulations. 1. The expanded definition of Impervious Surface in Chapter 24 is TECHNICALLY INCORRECT after the first sentence. a. While it is true that some surfaces made of concrete, asphalt, brick, or plastic are effectively impervious, the definition should NOT be based on the materials of construction -- It should be based on the infiltration rate of the material. b. There are many products made from concrete, asphalt, brick, and plastic that are partially or effectively PERVIOUS. Examples include: i. Permeable Pavers, ii. Porous Pavers or "Turf Blocks", iii. Permeable Concrete or Asphalt, iv. Pervious Pavers, and v. Artificial Turf. c. To exclude these products based solely on the material of construction is a significant stormwater management mistake that is UNREASONABLE AND INAPPROPRIATE. d. In Northeast Florida, rainfall events with an intensity of 4.0 inches/hour have a return period of 100 -years (US Department of Commerce, Weather Bureau, Technical Paper No. 25). Furthermore, most "typical" PERVIOUS surfaces in Atlantic Beach have an infiltration rate that is less than 4.0 inches/hour. e. Consequently, if test data or manufacturer's specifications confirm a long-term infiltration rate greater than or equal to 4.0 inches/hour, it should be classified as 100% PERVIOUS. f. I have personally conducted tests on pervious pavers and found the infiltration rates to be well above 4 inches/hour even after subjecting them to mud flows and applying water seal. g. A suggestion for correcting the definition of Impervious Surface is provided below: i. In the 2nd sentence, insert the word "may" before the word "include". ii. Insert the following sentence between the 2nd and 3rd sentences. "Construction products or the surface materials that may be impervious, as discussed above, can be classified as PERVIOUS, if test results or manufacturer specifications confirm that the long-term infiltration rate is greater than or equal to 4.0 inches/hour, and the base or lining is not impervious" iii. Delete the last sentence. This statement about pools is incorrect (see #5 below). 2. Chapter 24 regulations should be based on the Curve Number (CN) Method, NOT on a "modified" rational method, because the CN method is more accurate and justifiable. a. The CN method is now the required procedure by many municipal and regional authorities [Handbook of Hydrology, Maidment (1983)]. Page 2 of 5 COAB Stormwater Workshop 6/17/24 b. The CN method has largely replaced the rational method for calculating runoff volumes and peak runoff rates for several reasons: i. Literature values used with the rational method depend on storm intensity, duration and other drainage basin factors that require significant judgement, rather than justifiable or measurable data — it may be simple, it can be very inaccurate. ii. The CN method incorporates many of the physical characteristics (i.e., land cover, soil characteristics, and storm depth) that determine the runoff volume. iii. Consequently, the CN method is much more accurate and justifiable. iv. Also, peak runoff rates and the impact of onsite storage can be determined from CN methods. The procedures are discussed in Urban Hydrology for Small Watersheds (USDA, Technical Release -55, 1986). c. Since the objective is to determine the onsite storage needed to control excess runoff from impervious surfaces, the more accurate CN method should be used. d. Then, the results can be easily converted to a simple modified rational formula for regulatory simplicity. 3. The CN for a typical pervious surface in AB a. Using soil data for Atlantic Beach from the Natural Resources Conservation Service (NRCS web soil survey), I determined that a typical pervious surface in AB (i.e., upland, grassed open space in good to fair condition) has a CN of 65. b. Jones/Edmunds used the CN method in Attachment 1 to the SWMP Update (October 2018) and found the same exact value for typical pervious area in AB. c. I recommend that this CN -value (65) for atypical pervious area in AB, along with the standard CN for an impervious surface (98), be incorporated into Chapter 24, for clarity and consistency. 4. The Chapter 24 "modified" rational formula used to determine onsite storage is NOT CORRECT. a. Using the standard CN method, the calculation shows that the AB Code requires a property owner to install more than twice the onsite storage as is necessary to meet the stated objective to control the excess runoff from impervious surfaces. b. This error in Chapter 24 can be easily corrected by changing the constant at the beginning of the formula [Redline, Sec 24-89 (c)(9)] from 0.92 to 0.44. c. Furthermore, while it is true that the SWMP objective requires limiting both excess runoff volume and peak discharge rate, the CN methods in TR -55 show conclusively that if the onsite storage volume criteria is met, the peak discharge rate criteria also will be met. d. Consequently, there is no need to regulate peak discharge separately, and appropriately, the AB code does not provide a formula for calculating peak discharge. 5. Classifying all swimming pools as 50% impervious is INCORRECT, ARBITRARY AND UNJUSTIFIED. a. At best, this pool credit was based on consensus of the AB City Commission, with input from staff. The credit was NOT backed by sound science or engineering. b. Infinity pools have little or no freeboard and should be considered 100% IMPERVIOUS. Page 3 of 5 COAB Stormwater Workshop 6/17/24 c. Standard swimming pools use a surface skimmer to remove floating debris and the skimmer is usually installed between 4.5 and 5.5 inches below the deck or coping. This defines the normal water level and the pool's freeboard. d. If the pool freeboard is at least 4.3 inches, which is the case for most standard pools, runoff from the pool during the design storm event will be no more than from a typical pervious area in Atlantic Beach (i.e., the pool will not cause any excess runoff). Therefore, the pool should be considered 0% IMPERVIOUS. e. If for some reason, a pool's normal freeboard (PFB) is less than 4.3 inches, calculation of PERCENT IMPERVIOUS is simple and straight forward. Pool Freeboard >! 4.3 inches: %IMPERVIOUS = O% Pool Freeboard <4.3 inches: %IMPERVIOUS = [1-(PFB (inches)/4.3 inches)]*100 6. Artificial Turf, which AB previously considered pervious, is now being classified as impervious. a. The OF/IFAS paper, mentioned in the Comprehensive Plan Presentation, did not call artificial turf either IMPERMEABLE or IMPERVIOUS. As discussed above (issue #1), artificial turf should be classified on its ability to infiltrate water. b. I have seen data from artificial turf manufacturers (independent testing labs) that show infiltration rates exceeding 500 inches/hour. c. The OF/IFAS paper relied on other studies, which are not directly applicable to AB for SEVERAL reasons: i. Just one example, the authors point out that this experimental setup is most appropriate for TEMPERATE climate conditions. Atlantic Beach is considered HUMID SUBTROPICAL. There are several other reasons why this study is NOT APPLICABLE. ii. The depth(small) and duration(short) of the simulated rainfall events. iii. The relatively small plots, and high simulated slopes when compared to AB. d. The redline version of Chapter 24 states that artificial turf is prohibited within the dripline of regulated tree. This statement is NOT JUSTIFED OR JUSTIFIABLE. Even if the impervious character of artificial turf were somehow justified, it would NOT justify the prohibition. There are numerous examples of truly impervious surfaces within the dripline of regulated trees that have been in place for years without an adverse impact to the tree. 7. Professional Engineering Certification As a Professional Engineer, I would suggest that permit applications, submit with plans and specifications, signed, and sealed by a Florida PE should be reviewed by a PE. I would suggest the following language be included in Chapter 24: If a Professional Engineer (PE), licensed in the State of Florida, provides the COAB with a signed and sealed engineering report for an onsite stormwater management system (including necessary plans, specifications, and calculations), and certifies that the system meets the objectives and requirements of Chapter 24, only the City Engineer, or a licensed engineer under the City Engineer's responsible charge, shall review the plans and approve/disapprove the permit. Furthermore, If the COAB chooses not to review the plans within a reasonable time Page 4 of 5 COAB Stormwater Workshop 6/17/24 (TBD), the permit should be automatically approved. However, if the City Engineer requests further information from the PE, the review clock stops until the PE responds. This is not intended to preclude a property owner from providing the COAB with the necessary information fora permit. Itis intended to ensure that the work ofa licensed Professional Engineer is reviewed by a similarly qualified engineer. 8. One Last Point. One of the unintended consequences of overreach when establishing regulations is that the citizens begin to ignore them, request more and more exceptions, or may even litigate. I can attest to the fact that some of this is happening in AB with respect to the stormwater regulations. a. Regulations must be based on sound science and good engineering practices. b. To gain acceptance by those regulated, they must be APPROPRIATE, JUSTIFIED, AND CONSISTENT. THANK YOU FOR LISTENING TO MY CONCERNS. ANY QUESTIONS? Page 5 of 5 COAB Stormwater Workshop 6/17/24 10.00 of WC 7.00 N. 1� 5.00 4.00 3.00 2.00 1.00 0.00 9.30 Onsite Storage (Based on Excess Runoff) 8.56 COAB Code requires more than twice the onsite storage as is required to meet any of the SWMP OBJECTIVES 4. 2.33 Design Storm COAB Code SWMP Objective SWMP Objective Peak Volume Rate 1.25 WQ Control Hydrologic Soil Group & Areas For Atlantic Beach Data Source: NRCS, Web Soil Survey, 5/13/2023 Area of Interest: Intercoastal Marsh to Ocean, Hanna Park to Atlantic Blvd. Map Unit Area (ac) HSG 7 8.5 A 14 257.4 C 22 19.3 B 24 24.2 A 29 36.2 A 32 489.4 B 33 1.7 B 35 113.2 B 36 78.3 A 42 4.3 A 49 20.7 B 58 24.9 B 62 23.3 B 71 753.6 B Total Area = 1855 % of Area Total A = 151.5 8% Total B = 1446.1 78% Total C =1 257.4 14% Typical Pervious Area CN = 65 All A/D Soils Aassigned HSG = B. All HSG D Soils Dropped to be Conservative (i.e., to minimize runoff from the Typical Pervious Area). Tables.xlsx Table 1 1 of 5 6/14/2024 Hydrologic Soil Group (HSG) & Areas For Atlantic Beach Data Source: NRCS, Web Soil Survey, 5/13/2023 Area of Interest: Atlantic Beach Municipal Boundaries. Map Unit Area (ac) HSG 7 8.5 A 14 257.4 C 24 24.2 A 29 36.2 A 32 489.4 B 36 78.3 A 42 4.3 A 58 24.9 B 71 753.6 B Total Area = 923.2 % of Area Total HSG A = 151.5 16% Total HSG B = 514.3 56% Total HSG C = 257.4 28% Typical Pervious Area CN = 65 All A/D Soils Further Evaluated: Based on Drainage Class, Surface Texture, Wet Season Depth To Water Table, and Hydric Rating. All HSG D Soils Dropped to be Conservative (i.e., to minimize runoff from the Typical Pervious Area). Tables.xlsx Table 2 2 of 5 6/14/2024 Estimate of Runoff and Onsite Storage Coefficients Based on Standard Curve Number Method. Atlantic Beach Design Storm = 9.3 inches (25 -year, 24-hour) Required Onsite Storage Volume = CAR 12 cu. ft. Reference: AB Municipal Code Sec. 24-68(b)(9) Reasonable Value for C = 0.97-0.53 = 0.44 r NOT 0.92, as used in AB Municipal Code The rational or the modified -rational methods are designed to predict peak discharge rate. IDF Curves for Jacksonville, FI show that a 9.3 inch rainfall would have a duration of at least 24 hours. SCS CN method uses a hydrograph method and is based on 24 hour rainfall events. SCS CN method is more appropriate for calculating runoff volumes. CONCLUSION: The AB Municipal Code is requiring home owners to install more than twice the onsite storage volume necessary to control runoff from the regulated impervious area during the design storm event. Reference HEC -HMS Technical Reference Manual (USACE) Tables.xlsx Table 3 3 of 5 6/14/2024 Typical Pervious Impervious RUNOFF CALCULATION Area Area Average CN for Area 65 98 Soil Storage (inches) 5.4 0.20 Initial Abstraction [la] (inches) 1.1 0.04 Total Runoff (inches) 4.97 9.06 Equivalent Runoff Coefficients 0.53 0.97 Required Onsite Storage Volume = CAR 12 cu. ft. Reference: AB Municipal Code Sec. 24-68(b)(9) Reasonable Value for C = 0.97-0.53 = 0.44 r NOT 0.92, as used in AB Municipal Code The rational or the modified -rational methods are designed to predict peak discharge rate. IDF Curves for Jacksonville, FI show that a 9.3 inch rainfall would have a duration of at least 24 hours. SCS CN method uses a hydrograph method and is based on 24 hour rainfall events. SCS CN method is more appropriate for calculating runoff volumes. CONCLUSION: The AB Municipal Code is requiring home owners to install more than twice the onsite storage volume necessary to control runoff from the regulated impervious area during the design storm event. Reference HEC -HMS Technical Reference Manual (USACE) Tables.xlsx Table 3 3 of 5 6/14/2024 Runoff Coefficient required to Keep Peak Discharge from Impervious Area equal to Peak Discharge from Pervious Area' 25-Year 24-Hour Depth = 9.3 inches Runoff Pervious CN = 65 Qp = 4.97 inches Impervious CN = 98 Qi = 9.06 inches Rainfall Distribution = Type III Qi-Qp = 4.09 inches Pervious la = 1.077 inches Table 4.1 TR-55 Pervious la/P = 0.1158 Impervious la = 0.041 inches Table 4.1 TR-55 Impervious la/P = 0.0044 Peak Discharge Coefficients: Pervious Impervious Co = 2.471685 2.457317 C1 = -0.51846 -0.52206 C2 = -0.16808 -0.18188 Time of Concentration = 0.5 hr Min=0.1, Max = 10 Unit Peak Discharge qu = 409.7562 csm/in 396.268846 csm/in qo = Qp*qu(p) = 7.3E-05 cfs/ft2 Peak Pervious Unit Outflow Rate qi = Qi*qu(i) = 1.29E-04 cfs/ftz Peak Impervious Unit Inflow Rate qo/qi = 0.567173 Vs/Vr = 0.25 Onsite Storage Volume (ft) = 0.25 * P(inches)*Imp Area(ft2)/12 To Control Peak Runoff Rate the coefficient should be = 0.25 To Control Runoff Volume the coefficient should be = 0.44 The RO Coefficient in the AB Code = 0.92 Conclusion: If you control RO volume, you will control peak runoff rate Note 1: Calculation Method from Urban Hydrology forSmoll Watersheds, TR-55, USDA, June 1986. Note2: Lot size = 0.5 acres L = 209 ft n = 0.35 2-yr 24-hr Depth = 4 inches Land slope = 0.02 ft/ft tc = 0.5 hr Tables.xlsxTable 4 4 of 5 6/14/202412:44 PM Pool Pervious Credit Tablet Design Storm Volume = 9.3 Inches Pervious Area CN = 65 Impervious CN = 98 Typical Pervious Area Runoff = 4.97 Inches Impervious Area Runoff = 9.060 Inches Total Pool Pool Pool Pool Freeboard2 Runoff Pervious Percent (inches) (inches) Credit (%) Impervious Comments 150.24 9.060 0% 100% Example: infinity pools 1.0 8.30 19% 81% 2.0 7.30 43% 57% Interpolate between values, if 2.3 7.00 50% 50% nessary. 3.0 6.30 67% 33% 4.0 5.30 92% 8% 4.3 4.97 100% 0% 100% Pervious, No Extra Credit 5.0 4.30 116% -16% Pervious credit values above 100% or negative percent impervious values represent extra storage credit that could be used to offset other impervious areas. (See Example Beelow) 6.0 3.30 141% -41% 7.0 2.30 165% -65% 8.0 1.30 190% -90% 9.0 0.30 214% -114% 10.0 -0.70 239% -139% 11.0 -1.70 263% -163% 12.0 -2.70 287% -187% 1 Based On Curve Number Method 2 Vertical distance between normal pool water level and overflow elevations. 3 Example: If pool freeboard is 8.0 inches, impervious area credit would equal: 0.90 x Pool Area. Tables.xlsx, Tab: Table 5 5 of 5 6/14/2024 12:44 PM Procedure used by Gregory Powell, PhD, PE to Evaluate Pervious Paver Permeability. (Paver #1) Step 1: Obtained pervious paver from local distributor. Step 2: Built plexiglass container to enclose pervious paver and sealed all sides with silicone sealant. Step 3: Tested the containment seal around the paver and added sealant to the bottom edge of paver adjacent to plexiglass. Step 4: Tested the new (clean) pervious paver (n=8). The 95% LCL of the permeability was 283 inches/hour. Step 5: Flushed over a gallon of muddy water through the paver and carefully removed the 1/2 inch of mud that had accumulated on the surface. Step 6: Tested the "poorly maintained" paver (n=3). The 95% LCL of the permeability was l inches/hour (5 times the AB 100 year storm intensity is 4 inches/hour). Step 7: Dryed the "poorly maintained" paver for two days (no additional cleaning) and retested (n=6). The 95% LCL for permeability was inches/hour (not statistically different from first muddy test). Step 8: Washed off the surface of the paver with tap water and let it dry for two days. Applied Thompson's Water Seal with spray applicator, as suggested on label, and let paver dry for two days. Step 9: Tested pervious paver after applying Thompson's Water Seal (n=5). The 95% LCL of the permeability was 120 inches/hour. Calculation of Permeability: The pervious paver/containment frame: Length = 7.75 inches Width = 3.125 inches PP Surface Area = 24.22 sq.in 4 cups of water = 57.75 cu. inches t(sec) = time to infiltrate 4 cups of water Permeability (in/hr)= (57.75(cu.in.)*3600(sec/hr)/(t(sec)*24.22(in^2)) Conclusion: Permeability of "poorly maintained" pervious paver was at least 21 inches/hour or 7.4% of the new (clean) value. Even if the final permeability of the poorly maintained Pervious Paver were only 1.5% of the value when new, it would still infiltrate a 1 -hour 4" storm, which is a 100 year storm event. This is consistent with EPA NPDES (EPA -832 -F -21-031W, December 2021) assessment of pervious pavers (https://www.epa.gov/npdes). Pervious Paver #1 Data Volume = 4 cups of clean water Trial Time (sec) Inches/hr 1 17.3 496 Leaks observed, data not used 2 16.8 511 Leaks observed, data not used 3 16.2 530 Leaks observed, data not used 4 15.2 565 Leaks observed, data not used Added silicone sealant to bottom of seam around edge of paver. 5 6 23.5 25.0 365 Filling pore spaces, data not used 343 Filling pore spaces, data not used 7 29.0 296 Stable values 8 29.8 288 Stable values 9 28.9 297 Stable values 10 32.4 265 Stable values 11 29.3 293 Stable values 12 29.9 287 Stable values 13 29.5 291 Stable values 14 27.8 309 Stable values Count 8 8 Average Day 2 29.6 291 in/hr Std Dev Day two 1.30 12.32 STD ERR of Mean 0.46 4.36 95%UCL 31.9 283 95%LCL of new Pervious Paver 15 210 41 After flushing muddy water through Paver 16 301 29 After adding more mud to the top of Paver 17 297 29 Count 3 3 Average= 269 33 STD Dev = 51 7 Std Err of Mean = 29.7 4.1 95%UCL= 356 95%LCL poorly maintained Pervious Paver Page 1 of 2 1 18 251 34 Scraped off the excess mud from top of paver. 19 296 29 No washing 20 285 30 dryed-out the muddy paver for two days 21 270 32 22 250 34 23 235 37 Count 6 6 Average= 265 33 STD Dev = 23 3 td Err of Mean = 10.4 1.3 95%UCL= 285 30 95%LCL poorly maintained Pervious Paver After drying for 2 days After washing off top of paver with water (no pressure) and letting paver dry for two days. Applied Thompson Water seal to top of paver and let dry. 24 68 126 25 68 126 26 70 123 27 72 119 28 71 121 Count 5 5 Average= 70 123 STD Dev = 2 3 Std Err of Mean = 0.8 1.4 95%UCL= 72 120 95%LCL After Thompsons Water Seal Conclusion: Even if the final permeability of the poorly maintained Pervious Paver were only 1.5% of the value when new, it would still infiltrate a 1 -hour 4" storm, which is a 100 year storm. Page 2 of 2 Pervious Paver #2 Area 9.5 in X 6.25 in = 59.38 in^2 4 cups of water = 57.75 in^3 New Clean Water Test Paver #2 Trial Time (sec) inches/hr 1 15 233 2 16 219 3 16 219 4 15 233 5 15 233 6 16 219 7 14 250 8 15 233 Count 8 8 Average 15 230 S.D. 0.71 10.85 Std Err Mean 0.25 3.84 95% UCL 16 237 95%LCL 15 223 IV Notes: flushed over 2 gallons of muddy water through paver, rinsed off excess mud (no pressure cleaning) and let dry for 2 days. Test of Dirty Paver #2 Trial Time (sec) inches/hr 1 36 97 2 39 97 3 41 90 4 41 85 5 38 85 6 37 92 7 38 95 8 36 92 Count 8 8 Average 38 92 S.D. 1.98 4.69 Std Err Mean 0.70 1.66 95%UCL 40 95 95%LCL 37 89 Notes: Rinsed off surface of paver and let dry for a day. Applied water seal with spray bottle and let dry before test. Thompson's Test of Paver #2 Trial Time (sec) inches/hr 1 44 80 2 45 80 3 44 78 4 43 80 5 4S 81 6 42 78 7 39 83 8 40 90 Count 8 8 Average 43 81 S.D. 2.25 3.95 Std Err Mean 0.80 1.40 95%UCL 44 95%LCL 41 J78 Conclusions: 4.0 inches/hour is a 100 -year return interval for Northeast Florida (COAB) When new, the paver has a permiability of 223 inches/hour (more than 55 times the 100 -year rainfall intensity). After pouring more than two gallons of muddy water through the paver the permeability is still atleast 89 inches/hour (22 times the 100 -year rainfall intensity). After rinsing the surface of the dirty paver, letting it dry, and applying Thompson's Water Seal to the paver the permeability was still 78 inches per hour (almost 20 times the 100 -year rainfall intensity) Page 1 of 1 CITY OF ATLANTIC BEACH IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: 17 Z Name:y C A -ti 0/--1 &W -S- Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: Phone #: Email: PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH U IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: %//%/ �OZL� Name:n1,e Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: AR Phone #: 3z) 6 1' 75 2 � 3z7�8 Email:Cl'GL_eL� / / /11h•�il L �� �/�57'G, Gil PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): 0G-1�GJS�G� AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH (4) IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: ��/� Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: Phone #��D�� �SS— Syl�� Email: PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: Z- Name:"a Z //% Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING Y� O/ UR CONTACT INFORMATION BELOW IS OPTIONAL: / Address: .1 / (8 -6A k - (f 12C /--e) Phone #39<'_>,� 3�✓✓� Email: PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDAIT M # r—Lbi &c, OR SUBJ)ECT TO BE DISCUSSED (DESCRIBE BELOW) rl -,- /—o 6-17-24 Dear Mr. Williams, I received your 02/16/2021 email and it's appended report from your stormwater supervisor "Matt." It is telling that Matt's first comment is to make an unwarranted accusation against the citizen who made the complaint: "There was a slight impediment at the entrance to the swale where it appears the homeowner piles their yard waste, we opened that up and got it flowing faster." If Matt had carefully examined the "waste" removed when the swale was "opened... and flowing faster," he might have noted that it is a slurry of mud and leaves. (I can furnish photos.) This is typical of what is washed from 19'b Street, down the west lane of Oak Circle, every time it rains. And it typically accumulates at the entrance to the swale, blocks it, and floods the street. In fact a considerable amount of 19' Street's stormwater is drained to the swale via Oak Circle. This homeowner (and none other to my knowledge) has never piled any yard waste into any part of the swale. (The other residents of Oak Circle can attest to this.) On the contrary, before my recent coronary surgery, I have been clearing (by hand) both the swale and the street for years -- though with little effect. Matt is correct when he states: "The main issue lies in the road itself." Stormwater drainage (flooding) has been a serious problem on Oak Circle for as long as I have been able to observe it (about 30 years). Some years ago (when, I can't recall), the City attempted to mitigate the problem by digging up a narrow strip of the street's paving, then repaving this strip, leaving a slight indentation down its length. It was not deep enough, nor properly pitched, nor effective. I understand that this particular series of rainstorms was unusual, but Oak Circle's flooding is chronic. We've been waiting for Matt's long-term solution long enough. I beg the City to do more than "continue to keep a close eye on this." Sincerely, Karl Klein CITY OF ATLANTIC BEACH IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date:s — 01 �ld Z) Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon requestkf�o PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: AAP3nF2 Email: _Ii PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE TSCUSSED (DESCRIBE BEL 1 „ e%I . n � 1 „ C-,�� , I C, - ffnC)p-1I'm /--V, A Cal i CITY OF ATLANTIC BEACH U IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THEE] MEETING. Date: \ kd 1 1 T Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: Phone #: �' �/� Email: c[i PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH IF YOU WISH TO ADDRESS THE CITY COMMISSION.AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Name: vie - Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: Phone #: Email: PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH v IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO TH E G. UL� Date: Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING Y)QUR CONTACT INW"ATION BELOW IS OPTIONAL: Address: Phone #: Email: PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): I maL.; V -66A AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH Ma IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: Phone #• Email: '1 , PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH U/ IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. , / If Date: / l / /y� Name: 1 1Lf'� Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: ,� ���� I Phone #• � � Email: 1 f1�t7 ���; ��/ � • CC�/Y1 PER7 OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH v IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: (D 14 Name:t-- Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: 1-11 ?- M y A ` -'- Phone #: °' - 0*' -3 `r- 44"s Email: PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THEM ETING. Date: 177,:90 Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING- YOUR CONTACT INFORMATION BELOW IS OPTIONAL: / Address: ' � l �' �� Phone #:3-01 37D 92157 Email: eeo_� �o yo^, S'o 2 3 Oa a t e O PA PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # 2 OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH QV IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: t� `� — 2 Name: (IIN1n(A L.-AN'I Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT INFORMATION BELOW IS OPTIONAL: Address: Phone #•� Qi %� Z �) 4!�D Email: L n J C(G Ct r1 (P C l ti (I PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW) CITY OF ATLANTIC BEACH �O -/7-2-q �S IF YOU WISH TO ADDRESS THE CITY COMMISSION AND COMMUNITY DEVELOPMENT BOARD ON ANY MATTER AT THIS MEETING, PLEASE COMPLETE AND GIVE THIS FORM TO THE CITY CLERK PRIOR TO THE MEETING. Date: Name: Please Note: Florida has a very broad Public Records Law. Most written and recorded communications to or from State and Local Officials and agencies regarding State or Local business are public records available to the public and media upon request. PROVIDING YOUR CONTACT CONTACT INFORMATION BELOW IS OPTIONAL: Address: 2�(/ Phone #• zo Z T7? 3 FS 3 Email: PERSON OR COMPANY THAT YOU REPRESENT (IF APPLICABLE): AGENDA ITEM # OR SUBJECT TO BE DISCUSSED (DESCRIBE BELOW)