Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Post Harvey Flood Data and the Future of Resilient Infrastructure

64 views

Published on

John Blount, Harris County Engineer

In late August, a downgraded tropical storm Harvey, which made landfall as a category 4 hurricane just days before, stalled over southwest Texas causing torrential flooding throughout the region. Unincorporated Harris County alone was inundated with in excess of a trillions gallons of storm water over 4 days, enough to fill the Astrodome 3200 times. In the aftermath of the unprecedented event, local officials were left to shepherd constituents through recovery and back to a sense of normalcy.

In this presentation, the county engineer, John Blount, gives a detailed account of the after events of Hurricane Harvey and its effects on the environment, infrastructure and community. Mr. Blount will analyze flood data yet to be released to the public, in order give the audience a perspective of just how devastating Harvey’s flood waters were. This session will breaks down the county facilities destroyed by Hurricane Harvey and John’s vision to respond with resilient solutions instead of temporary fixes because with the frequency and severity of recent storms, this could be the new normal.

Published in: Engineering
  • Be the first to comment

Post Harvey Flood Data and the Future of Resilient Infrastructure

  1. 1. Office of the County Engineer John R. Blount, P.E. June 2018 Hurricane Harvey A Response to Disaster
  2. 2. Agenda • Public Safety • Debris Operations • Private Damage • Harris County Facilities • Sustainability Initiatives
  3. 3. Day One of Recovery Priorities: • Safety of Employees • Timely Damage Assessments • Aggressive Recovery Plan • Continuity of Government Tuesday August 30th
  4. 4.  13,000+ centerline miles of roads maintained  Average of up to 50,000 vehicles per day  Majority are local roads  Wide range of ages, original design criteria  800+ bridges  2 ferry boats at Lynchburg  900+ traffic signals  500+ school zone flashers  250 miles +/- of fiber optic cable for ITS and signal operations  8 major communications hub buildings Note: This list does not fully include Harris County Toll Road assets Harris County Transportation Asset Summary
  5. 5. Immediately following Hurricane Harvey, Harris County Engineering Department rapidly mobilized to achieve the following key accomplishments:  Successfully completed over $10 million dollars in repairs to the Lynchburg Ferry in less 180 days  Rapidly repaired 12 washed out roads to allow pedestrian/emergency vehicle access Most Notable: Market Street ($1.8 Million) & Garret Road ($950k)  Inspected 886 bridges in 2 week, to ensure structural stability and public safety Most Notable: Clay Road over South Mayde Creek ($310k)  The HCED was able to quickly respond to and address over 200 Damaged Items through the use of a flexible and adaptive staff organization HCED Key Accomplishments Roads & Bridges
  6. 6. Market Street • Section of Road (250’ x 200’) • Four-way intersection washed out. • Roadway re-opened in less than 120 days later. After RepairsBefore Repairs
  7. 7. Immediately following Hurricane Harvey, Harris County Engineering Department rapidly mobilized to achieve the following key accomplishments:  Successfully completed over $10 million dollars in repairs to the Lynchburg Ferry in less 180 days  Rapidly repaired 12 washed out roads to allow pedestrian/emergency vehicle access Most Notable: Market Street ($1.8 Million) & Garret Road ($950k)  Inspected 886 bridges in 2 week, to ensure structural stability and public safety Most Notable: Clay Road over South Mayde Creek ($310k)  The HCED was able to quickly respond to and address over 200 Damaged Items through the use of a flexible and adaptive staff organization HCED Key Accomplishments Roads & Bridges
  8. 8. Clay Rd. over South Mayde Creek Items Damaged and Repaired: • Concrete Slope Paving Failure • Debris Build Up After Repairs Before Repairs
  9. 9. In addition to the key road & bridge accomplishments, HCED successfully mobilized to inspect and repair traffic signals across the County, including:  Completed $2 Million in repairs  Inspected over 900 signals in 4 days  Inspected 347 communication locations in 2 weeks  Replaced 58 damaged signal cabinets  Repaired/Replaced 95 damaged communication locations HCED Key Accomplishments Traffic Signals
  10. 10. Desi HCED Recovery Stats FHWA Project # FEMA Project # FHWA Cost FEMA Cost Roads 6 67 $13,553,036.40 $3,903,978.69 Bridges 11 50 $1,721,574.27 $2,167,492.14 Traffic Signals 69 All Damages were covered by FHWA $1,954,288.42 All Damages were covered by FHWA Total 86 117 $17,228,899.09 $6,071,470.83 *Figures are current as of 5/21/2018
  11. 11. Debris Removal Above: First pass of the Woodforest subdivision in Crosby. Below: Harris County Debris team at the Tomball DMS site.
  12. 12. Debris Removal Highlights of the first 20 days  Started hauling 4 days after the event  Hauled the equivalent of Tax day floods every two days  1.2 Million Cubic Yards Hauled To-Date
  13. 13. Debris Removal August September October November December 1st Pass – 31 days 2nd Pass – 32 days 3rd Pass – 39 days Highlights  Started hauling 4 days after the event  Hauled the equivalent of Tax day floods every two days  1.2 Million Cubic Yards Hauled To-Date
  14. 14. Unincorporated Harris County Damage • 31,982 Flooded – Residential • 120 Flooded -Commercial Recovery • 505,000 structures visually inspected • 4,300 in-home residential inspections • 31,000 Residential permits issued Free of Charge Private Damage
  15. 15. • 75,000+ homes were built in subdivisions developed in 2009 and later utilizing the current infrastructure requirements for drainage and extreme event flow analysis. • Of those homes, only 467 flooded during Harvey, or 0.6% • Zero homes were substantially damaged Analysis of Homes Built in Subdivision Development in 2009 and later
  16. 16. Freeboard Height vs Flood Insurance Premium
  17. 17. Greater Texas 100 yr Flood Zone Single Family A Zones and Shaded X Zones below BFE Houston 12” Harris County 18” San Antonio Habitable buildings prohibited in SFHA Bexar County, TX 12” Fort Worth 24” Tarrant County, TX 24” Dallas Habitable buildings prohibited in SFHA Dallas County, TX 12” Freeboard Comparisons
  18. 18. 100 Year vs 500 Year
  19. 19. No Standard Current StandardOld Standard
  20. 20. Harris County Floodplain Regulations Jan 1 2018 Revision
  21. 21. Permits Within Non-Conforming Subdivisions
  22. 22. Structural Requirements Regardless of the class of permit issued (I or II), all Non-Conforming Subdivisions must show, in addition to any other requirements, the following elevations are met: 1. If the structure is a single family residence the finished floor shall be a minimum of 12 inches above the highest adjacent natural grade when measured 10 feet from the edge of the slab or 12 inches above the crown of the adjacent street which ever results in the highest elevation (An exception may be granted on sloping properties where the crown requirement is not achievable). 2. If the structure is other than a single family residence the slab shall have a minimum of 6 inches of exposure to adjacent grade and be at least 12 inches above the crown of the adjacent street (An exception may be granted on sloping properties where the crown requirements cannot be achieved). 3. To verify this for structures outside the floodplain, a newly created HC Foundation Certificate will be required.
  23. 23.  No fill may be used to elevate structures in the 1 percent or 100-year flood plain. Structures may be constructed on an open foundation, such as piers, or on continuous foundation walls with properly sized and located openings. All foundations are required to be designed by a registered professional engineer. The drawings shall clearly show compliance with all provisions of these regulations. Fill may be used in coastal surge zones where flood plain fill mitigation is not an issue, however the standard for foundations remain the same.  All structures shall be designed to withstand a three second gust basic wind speed of 120 miles per hour. This will ensure structural rigidity, should design flood elevations be exceeded, or the structure requires elevation in the future. Additional Requirements
  24. 24. All structures in the floodway must now meet the requirements that were previously only required in the San Jacinto floodway. I. Foundation Type: The foundation system shall consist of a driven pile or a drilled pier foundation system II. Type and Size of Driven Pile: Driven piles shall consist of either twelve (12) inch (minimum) square pre-stressed concrete piles or fourteen (14) inch (minimum) diameter steel pipe piles with a closed end. III. Type and Size of Drilled Pier: Drilled piers shall be eighteen (18) inch diameter (minimum) and straight-sided (no belled or under-reamed base) IV. The minimum embedment below natural grade for driven piles and drilled piers shall be twenty (20) feet V. The individual piles or piers shall be braced horizontally with reinforced concrete tie beams connecting the pier/pile caps each way (not diagonally). For piles that extend above natural grade and act as column supports for the structure, a reinforced concrete collar shall be cast around each pile at the groundline, and the collars shall be connected each way with reinforced concrete tie beams VI. Additional construction requirements Building in the Floodway
  25. 25. Home Buyout Program
  26. 26. Additional Highlights • All requirements specific to the 10 year floodplain have been removed. • For the purpose of rebuilding after a flood event, any single family residence that received flood damage, but the finished floor is at or above the 1 percent or 100-year flood level, cannot be substantially damaged, if they meet the minimum federal elevation requirement for rebuilding. • Where a conditional letter of map change has been obtained or will be obtained from the Federal Emergency Management Agency for property which has been elevated by the use of fill above the elevation of the 1 percent or 100-year flood, and detailed plans have been approved by Harris County a Class I permit will be issued. • Floodplain fill mitigation requirements do not apply to Coastal Areas where floodplain fill mitigation is not an issue. • In areas of combined coastal and riverine flood hazard, floodplain fill mitigation requirement only applies for the portion of fill placed below the riverine flood hazard elevation as provided in the FIS or an approved hydraulic model
  27. 27. Return On Investment
  28. 28. Raised Floor Systems
  29. 29. Residential
  30. 30. New Residential Foundations Helical Pier Foundation Permanent Wood Foundation
  31. 31. Durability of Timber Piling Some well know examples of the durability of timber piling: • At Ephesus, in what is now Western Turkey, a temple was constructed around 6000 BC and reconstructed 300 years later on the original untreated timber pile foundation. • Near Rochester England, excavations of old Roman roads revealed timber piles 1900 years old in excellent condition. • The first masonry London Bridge built in 1176 stood on untreated elm piles and lasted 600 years • The Campanile Tower in Venice was rebuilt in 1902 on the original 1000 year old timber piles which supported the original structure built in 900 AD. • The sill excellent condition of piles used for the Circus in Arles (France), built in 148 AD on wetlands, can be seen in the museum at the site. Permanent Wood Foundation
  32. 32. Building In Non-conforming Subdivisions Return on Investment • Lower risk of damage during heavy rain event • Lower flood insurance premium • Lower cost if elevation is needed in the future Foundation Type Cost per add’l foot Concrete block piers $890 Crawlspace with concrete block walls $1,850 Crawlspace with poured concrete walls $2,155
  33. 33. Slab on-grade Elevation Single-family residential raised to pier and beam foundation in the Meyerland area Single-family residential raised to footing and stem wall foundation in the Meyerland area
  34. 34. Commercial Elevated commercial building in the 100 yr floodplain with subsurface detention capacity.
  35. 35. County Facilities Quick Response After the first 6 days of recovery all 180+ Harris County operated buildings were assessed for damage and all damaged structures were already repaired or in proposal process for repairs
  36. 36. Criminal Justice Center (CJC) Pre-Harvey Post-Harvey Scope The Criminal Justice Center experienced flooding up to 21 inches in the basement and 2 inches on the first floor. In addition, the facility had water damages on multiple floors covering a combined area of approximately 150,600 square feet.
  37. 37. WHAT WILL BE DONE  Restoration of damaged areas caused Hurricane Harvey  Flood Mitigation and Protection measures to protect the facility from potential future flooding events, in compliance with newly-adopted flood plain regulations. Those protective measures include: o New flood barriers around the CJC and replacement of existing flood gates in the basement, first floor and garage parking level. o Critical building equipment relocated to the First Floor on platforms 4’ above the finish floor. o New durable and water-resistant finishes to reestablish building operations quickly.  Building Improvements Highlights o First floor lobby expansion and reconfiguration to alleviate congestion at Security Screening and Public Elevator Lobby areas. o Five new elevators to be added to expand vertical transportation capacity and modernization of existing elevators. TIMETABLE & UPCOMING MILESTONES  On June 4, 2018 – Phased reopening starts with the opening of Floors 17, 18, 19, 20, available for some court functions. Portions of the First Floor Lobby will be accessible and elevators servicing the available upper floors will be operational.  Phased design and construction will continue through at least 2019. Criminal Justice Center (CJC)
  38. 38. Harris County Jury Assembly Pre-Harvey Post-Harvey Scope Jury Assembly experienced flooding in excess of 108 inches in the basement level and 120 inches in the adjacent tunnel areas. The area of damaged encompassed approximately 31,773 square feet. All flooring, sheetrock walls, furniture, electronics, pipe insulation, mechanical and electrical equipment in flood areas was determined to be unsalvageable.
  39. 39. WHAT WILL BE DONE  Flood Mitigation and Protection Highlights o New flood door/protection at CenterPoint Vault to address the source of the Flood o New flood barriers at stair doors o Replacement of existing flood doors o Replacement of materials and finishes with flood resistant options o Replacement of assembly area seating with exterior-grade flood resistant options o New emergency sump pumps  Building Improvement Highlights o New enclosed/air-conditioned entry expansion at street level for 160-person queuing capacity TIMETABLE  Performed To-Date o Complete Building Damage Assessment and Water Intrusion Forensic Study was performed to locate the source of flooding for the building. o User-group meetings to explore and define areas of improvements based on current requirements. o Numerous Design studies and cost estimates have been performed to address flood protection and mitigation strategies as well as improvements to facility functions.  Upcoming Milestones o Design efforts are scheduled to start at the end of June 2018, and will continue through the end of the year, with construction projected to start in February 2019. o Estimated construction completion is November 2019 Harris County Jury Assembly
  40. 40. Sustainability Harris County evaluates sustainable practices in all infrastructure projects. Examples:  All new county buildings to be LEED certified  Only comprehensive Low Impact Development (LID) regulation in the region  Ongoing sustainable research projects  Sustainable turf project  Net Zero test facility  Long-term storm water quality and quantity testing on Birnamwood  Upcoming sustainable practices  Testing products to produce “self detaining roads”  Developing low cost sustainable single family homes designs for CSCD
  41. 41. Burnett-Bayland Gym First LEED Platinum Award on the Texas Gulf Coast
  42. 42. Rainwater Harvesting Solar PV Panels Kalwall Skylight
  43. 43. Harris County’s First LID CIP Project - Birnamwood Drive LID Features –  Engineered Soils in Swales  Native Landscaping  Reduced Pipe Sizing  Rain Tanks and High Pervious Soils Native vegetation at Birnamwood Dr. Monitoring at Birnamwood Dr.
  44. 44. Net Zero Building  First self-sustaining facility in Harris County  "Our Great Region 2016 Diligence Award" (Honorable Mention) Monitoring system at Net Zero building
  45. 45. A Vision for the Future Completion date: Q4 2018 Net Zero Features: HVAC High-efficient 2-staged geothermal pump system Electrical LED fixtures w/ LPD design of 0.32 watts/sqft (70% less than power than allowed by code) Energy 182 KW Photovoltaic system will generate equal or more than the energy consumed to achieve “net-zero” rating Cost: Approx. $19,000,000 Lid Features: • Bio-swales • Storm Water Harvesting • Wetland Treatment Ponds • High-Performance Modular Bio-Filtration System PCT 4 Admin Service Center
  46. 46. Question? John.Blount@hcpid.org For additional information contact Carlos Perez at carlos.perez@hcpid.org

×