City of Englewood : Conclusions & Recommendations

Project Conclusion

FLOODPROOFING CONCLUSIONS

After looking at flood history, researching existing topography and structures, creating hydrologic and hydraulic models, reaching out to homeowners, and researching other publications on floodproofing we have formulated the following conclusions:

Strong confirmation of significant and frequent flooding in the area was found in the hydrologic and hydraulic calculations, in public outreach and comments, site visits, the photographic record, and in discussions with homeowners.
The hydrologic and hydraulic analyses confirm that, even in the 5-year storm event, the resulting runoff inundates a number of streets and floods both residential and commercial structures.
Floodproofing of individual residences is feasible for the majority of homes in inundation zones.
For homes in the deepest inundation locations, the most cost-effective floodproofing methods are unadvisable. Only raising the home above the flood elevation would provide adequate protection. Raising a home is expensive and complicated as it involves jacking, retrofitting the foundation, and retrofitting the architecture.

Most homes in inundation areas are eligible for flood insurance through the National Flood Insurance Program. Generally, homes not in a FEMA floodplain are eligible for flood insurance. Currently, this area is not a mapped FEMA floodplain.
Homeowners will need assistance in developing plans for floodproofing and will need good mapping resources to help them understand their risk.
A number of reported flooding locations are outside of the inundation areas reflected in the hydrologic and hydraulic calculations. This confirms that the granularity of the analysis (i.e. the amount of detail built into the modelling) does not have sufficient detail to account for all types of flooding. Specifically, street flooding near the downstream end of basins where more detailed street capacity calculations would be needed is not reflected, and flooding caused by additional obstructions such as sewer plugging, and solid fencing is not reflected either.

FLOODPROOFING RECOMMENDATIONS

The City has begun the process of addressing flooding, the first step being this study and public outreach. This process will involve many specific actions over a long period of time.

Based on our floodproofing study we are making the following recommendations:

A public outreach program should be developed to help residents understand their flood risk and assist them in evaluating the need for flood insurance in their location.
A public education and outreach program should be developed to assist homeowners with floodproofing.
Utilization of basements within flood inundation areas can be a high life safety risk, depending on the level of inundation and level of basement ceiling, as well as the physical abilities of the occupants. The City should contemplate a program of outreach to these homeowners and consider building and occupancy restrictions in inundation zones.
The City might consider other assistance in the form of grants and matching funds to assist homeowners financially

Homes in the deepest inundation areas (such as areas exceeding 3’ of inundation) will need special attention. Programs such as City buy back through a bond issue or assessment would likely be needed to generate the needed funds.
Solid fencing within inundation areas is creating diversions that exacerbate flooding on surrounding properties. The City should consider changes to its fence ordinance to restrict solid fencing in inundation areas.
Additional detail should be added to hydrologic and hydraulic calculations near the downstream end of basins since we have noted locations where additional street flooding is occurring that is not indicated in the current models.

OSP CONCLUSIONS

After researching historic storm events, looking at flood history, creating hydrologic and hydraulic models, reaching out to homeowners, and exploring alternative infrastructure improvements, we have formed the following conclusions:

Strong confirmation of significant and frequent flooding in the area was found in the hydrologic and hydraulic calculations, in public outreach and comments, site visits, the photographic record, and in discussions with homeowners.
The hydrologic and hydraulic analyses confirm that, even in the 5-year storm event, the resulting runoff inundates a number of streets and floods both residential and commercial structures.
Floodproofing of individual homes is feasible for the majority of homes that are in inundation zones.
A number of reported flooding locations are outside of the inundation areas reflected in the hydrologic and hydraulic calculations. This confirms that the granularity of the analysis (i.e. the amount of detail built into the modelling) does not have sufficient detail to account for all types of flooding. Specifically, street flooding near the downstream end of basins where more detailed street capacity calculations would be needed is not reflected, and flooding caused by additional obstructions such as sewer plugging, and solid fencing is not reflected either.

A plan to provide 100-year capacity storm sewer infrastructure does not appear to be feasible, although given enough funding a solution could be developed. Our conclusion was that, due to the size of a 100-year system, the associated cost of pipe construction, required modifications to existing utilities, and disruption to services, it is not practical to construct. For this reason, we did not provide a cost projection for the 100-year storm sewer design, but rather focused on more frequent flood events.
An inadequately sized storm collection and piping system is the main cause of residential flooding. This situation can be improved dramatically by upsizing the existing storm sewer system.
In locations where the deepest flooding occurs, additional floodproofing actions above and beyond sewer capacity improvement would be needed to protect homes from damage and to protect life safety of occupants.
Various possible locations were reviewed for detention, but no locations were identified for new detention facilities that would provide a cost effective reduction in flood hazard.

OSP RECOMMENDATIONS

Prioritize projects in accordance with this study. The decision on whether to prioritize other projects over the Oxford pipe will require input from the City Council. To see the list of recommended CIP projects, please refer to the OSP update page.
Discuss with the City the need for some more detailed hydraulics in a few specific locations where reported flooding is not reflected by the hydraulic model.
The consultant presented an option of re-establishing the drainageway from Broadway to Navajo Street. This option was removed from consideration by City Council and is not further discussed in this study. Final design and analysis may identify and further consider such an option.

Discuss whether to proceed with a 100-year estimate for comparison purposes.
Develop codes and policies for building on lots that are in within the Probable Area of Flooding.
Develop a public information process that conveys information to citizens about flood hazard, home safety planning, floodproofing, and related topics.

Raw Data

The following documents are copies of all workbooks, in-field notes, survey results, and other useful information that was used in the compilation of these results.

This is the raw field data for the 702 households/businesses that were visited in-person. This document outlines the address, important features (for flooding) of the building/lot, property and life safety risks, and comments about the property.

NOTE: A property was categorized “low life safety risk” if flooding was not an issue or if floodwaters would be below the main floor level and no basement was present.

A property was categorized “moderate (MID) life safety risk” if floodwaters were high enough to be above the main floor up to 2′ and no basement is present or a basement was present but had lower risk of being flooded/had egress windows.

A property was categorized “high life safety risk” if a basement was present with risk of full-inundation (floodwaters to ceiling) with only interior stair egress available or if a basement was not present but floodwaters were between 2-4′ on the main level of the home.

A property was categorized “critical life safety risk” if floodwaters reached more than 4′ on the property, if an exterior stairwell to the basement was the only visible source of egress from the basement, if the basement had risk of full inundation with heavy/deep flooding on the main level, or there was another anomaly with the property that would make escape from flooding dangerous or high risk.

This document is the raw data from the survey sent to 4,000 residents. 55 residents responded to this survey, answering questions such as details on the extent of flooding at their property, the history of floods at the property, the extent of damage, remediation measures applied, and contact information.

NOTE: This document was edited only to remove strong language.

These results were used to help compile the Flood Outreach document (see right).

These are copies of the notes taken in the field during the property walk-by visits. Some common abbreviations/keys to note are:

red or green L or P or at risk (red) or not at risk (green) life and property safety
WW - window well
G - garage,
CS - crawl space
FV - flood vents, and
CL - chain link fence

Each sheet has a keymap showing its location within the basin. Each house within the basins has a white circle with a number inside indicating the expected depth of floodwaters based on the 1998/1999 study interpolations. These depths were used to estimate where on the home (from the lowest grade point on the home) floodwaters will reach. This helped to determine the flood damage risk for each home.

This is a brief soils report for the study area as provided by the United States Department of Agriculture Natural Resources Conservation Service (NRCS)

This document is the full, report-style version of the pipe assessment report.

Letters were mailed to individual homeowners to obtain more information on flooding that occurred at individual properties, as well as the impact of that flooding.

Limitations of Report

The statements, conclusions, and recommendations offered in this report are based on information gathered as part of a desktop review and initial field investigations. Additional investigations are required to fully understand the condition of the system evaluated.

DISCUSSION WITH FEMA

On March 08, 2019, the Calibre team participated in a phone conversation with two representatives from FEMA. This discussion centered around flood insurance, grants for the city, as well as other regulations. Below is a summary of the main points of the discussion.

FLOOD INSURANCE

Anyone is Eligible for Flood Insurance

If the structure is more than 50% below ground
If the structure is built completely over water
Basement contents are not covered in NFIP. Electrical and mechanical systems and their requisite appliances (furnace, water heater, etc.) are covered, but household appliances and furnishings (couches, TV, etc.) are not covered.

Some private insurance companies provide flood insurance. If not, NFIP through the federal government is available. Private insurance has different rules, however, and could drop coverage for any reason. Flood insurance could not be cancelled by the insurer if it is through NFIP.
Retrofitting of basements is more expensive and harder than floodproofing a new build, but it is possible.
In the SFHA, residential basements cannot be floodproofed, but commercial basements can be retrofitted.
Englewood is not in a SFHA and therefore retrofitting is allowable.

POTENTIAL GRANTS

Pre-Disaster Mitigation Assistance Program

The PDM Program, authorized by Section 203 of the Robert T. Stafford Disaster Relief and Emergency Assistance Act, is designed to assist States, U.S. Territories, Federally-recognized tribes, and local communities in implementing a sustained pre-disaster natural hazard mitigation program.
The goal is to reduce overall risk to the population and structures from future hazard events, while also reducing reliance on Federal funding in future disasters.
This program awards planning and project grants and provides opportunities for raising public awareness about reducing future losses before disaster strikes.
FEMA requires state, territorial, tribal, and local governments to develop and adopt hazard mitigation plans as a condition for receiving certain types of non-emergency disaster assistance, including funding for PDM mitigation projects.
Project subapplications submitted for consideration for PDM funding must be consistent with the goals and objectives identified in the current, FEMA-approved State or Tribal (Standard or Enhanced) hazard mitigation plan along with the local or tribal hazard mitigation plan for the jurisdiction in which the activity is located.
Planning subapplications submitted for consideration for PDM funding must result in a mitigation plan adopted by the jurisdiction(s) and approved by FEMA.

Eligibility: The following are eligible Applicants to the PDM grant program:

States
U.S. Territories
Federally-recognized tribes
Local governments
Local governments are eligible subapplicants and can sponsor applications on behalf of homeowners to submit to the Applicant.

Application Process:

Subapplicants (i.e., local governments) submit mitigation planning and project subapplications to their State during the open application cycle. After reviewing planning and project applications to determine if they meet the program’s requirements, the Applicants (i.e,. States, U.S. Territories, or Federally-recognized tribal governments) prioritize and forward the planning and project applications in a PDM grant application to FEMA.
Locals (subapplicants) should contact their State Hazard Mitigation Officer or Federally-recognized tribal/local government official to obtain detailed information on the PDM application process.
Colorado State Hazard Mitigation Officer

Steven Boand, Disaster Recovery Manager
Colorado Division of Homeland Security and Emergency Management
9195 E Mineral Ave, #200, Centennial, Colorado 80112
Phone: (970) 385-1675 ext. 518306694, Fax: (720) 852-6750
E-Mail: steven.boand@state.co.us
Web Page: www.dhsem.state.co.us

Once FEMA reviews planning and project applications for eligibility and completeness, FEMA makes funding decisions based on the agency's priorities for the most effective use of grant funds and the availability of funds posted in the Notice of Funds Opportunity (NOFO) announcement on Grants.gov. The PDM program is a highly competitive grant program.
FEMA awards PDM funds to State, U.S. Territory, and Federally-recognized tribal Applicants, who in-turn provide subawards to local government Subapplicants.

FY 2019 Application Cycle:

FEMA will offer NOFO webinars, which is usually in Aug thru Sep, for potential applicants (States) prior to opening the application period, which is usually from Oct 1st thru Jan 31st.

The Colorado Division of Homeland Security and Emergency Management (DHSEM) encourages local communities throughout the State interested in learning more about this opportunity to contact one of the State Hazard Mitigation Specialists listed below for additional information.

Matt Arsenault: matt.arsenault@state.co.us , Mitigation Project Specialist
Deanna Butterbaugh: deanna.butterbaugh@state.co.us, Mitigation Project Specialist
Patricia Gavelda: patricia.gavelda@state.co.us, Mitigation Planning Program Manager
Mark Thompson: markw.thompson@state.co.us, Mitigation Planning Specialist

DHSEM is requiring sub-applicants use EMGrants to notify DHSEM of formal interest in submitting a sub-application for grant funding. Interested sub-applicants are encouraged to contact a Mitigation Specialist to determine if an active account in EMGrants exists or if a new account is required.

Below were the important DHSEM deadlines for FY 2018:

August 14, 2018 - Initial Notification to DHSEM of Project/Plan Interest
October 17, 2018 - Draft Benefit-Cost Analysis (BCA) Submitted to DHSEM for Review EMGrants
November 16, 2018 - Preliminary Application due to DHSEM via EMGrants
January 14, 2019 - Final Applications Submitted to DHSEM in eGrants
May 1, 2019 - FEMA Anticipated Funding Selection Date
December 30, 2019 - FEMA Anticipated Award Date

PDM projects for FY 2018 are capped at $4 million Federal share (with the exception of Resilient Infrastructure projects, which are capped at $10 million Federal share); communities may exceed this amount, but all additional costs will not be subject to the 75 percent Federal / 25 percent local cost share, and all costs exceeding this amount must be borne by the local community.

Advance Assistance: For the first time, FEMA is offering Advance Assistance grants under both PDM and FMA (Flood Mitigation Assistance). These grants are capped at a Federal share of $200,000 for PDM and $100,00 FMA. Advance Assistance can be used to develop mitigation strategies and obtain data to prioritize, select, and develop and design community mitigation projects and other related activities.

STANDARDS & RESOURCES

Resources used in preparing this website:

US Army Corps of Engineers. Flood Proofing Techniques, Programs, and References. Omaha: US Army Corps of Engineers, 2000. (pp. 1–32).
FEMA. FEMA P-259: Engineering Principles and Practices for Retrofitting Flood-Prone Residential Structures. FEMA, 2012.
FEMA. FEMA P-312: Homeowner’s Guide to Retrofitting: Six Ways to Protect Your Home from Flooding. FEMA, 2014.

MegaSecur-WaterGate. “MegaSecur | Products.” Retrieved 2018 10 25 from: www.megasecur.com/en/products/
US Army Corps of Engineers. Flood Proofing Regulations. Washington DC: Army Corps of Engineers, 1995. (pp. 1–85).
WMGB Home Improvement. “Advantages of Basement Egress Windows.” Retrieved 2018 10 15 from: www.wmgb.com/egress-windows/advantages-basement-egress-windows/