FEMA NO BASE FLOOD ELEVATION DETERMINED

We are fortunate (????) that in the last 25 years we have had three 100 year events so we have good knowledge of reality.

The following scenario may not work for insurance purposes, but the county accepts the results for building permits.

We have a lot of areas where 100 year zone is shaded, but no BFE's determined and the gradient is very steep.

So, if we can find locals who witnessed the storms and we are satisfied that their recollections are accurate, we can use evidence of high water as a BFE.

I repeat that this is only for the county and only for the purposes of issuing building permits.

Other than that it is a major effort for a full flood study at the location in question. And no one wants to pay for that.

Also, sometimes you can submit data to FEMA and they will make a determination of a BFE, but good luck.

More than half the elevations certificates around here have "BFE not determined". Fortunately the State Dept. of Natural Resources (now Dept. of Environmental Quality) has flood elevations on many lakes. I mark the form B10 box and write "Dept. of Natural Resources" in the blank. They have always accepted them no questions asked.

FEMA publishes a "Zone A" manual. http://www.fema.gov/library/viewRecord.do?id=2215

FEMA states that if the property is located in a subdivision of greater than 50 lots, or 5 acres, then the local flood plain manager must determine and provide a BFE. In other cases, it says you must contact any Federal, State, or local agency that may have knowledge of base flood elevations. If no one is willing to provide a base flood elevation, then you fill out section E.

I have done a few elevation certificates in a Zone A with no base flood elevations. I have always filled out the Section E. I have never had any issues.

Ditto on the Manual. Also, exhaust every possible source of information first; local floodplain official, Local or state highway department, other consultants, other State of Local Agencies.

As a last resort:

Use USGS Streamstats to determine your watershed discharges.

http://streamstats.usgs.gov/california.html

Use FEMA's Quick-2 program to determine your BFE.

http://www.fema.gov/national-flood-insurance-program-0/quick-2-version-20

If a river, then look for the nearest bridge, obtain DOT flood study if available. You can use the elevation at the bridge for anything downstream or can send to FEMA and they will pick one from the cross-sections if you need it upstream and it's within the study area. May need to make a FOIL request and can take time.

If no bridge study close enough, use an approximate method (these are in the mentioned manual). For a LOMA, FEMA may want to use their own approximate method determination and this could take time for them to get one of the approved contractors out and then review the info..

If a lake, may be the only thing you can do (in absence of getting all landowners around the lake to pitch in and pay for a flood study) is show improvements in relation to mean high water. This can substantially lower the cost of flood insurance depending on the results but can't be used for a LOMA. The local flood plain manager can request a study, but in our area these requests have not been complied with as other more risk prone areas take precedence.

I generally try to convince clients to pay the extra and have me pursue the LOMA for them if possible. Things may have changed, I have not done these for 10 years or so. When I did, all of them were zone A no bfe.

With the recent changes I know the old elevation certificates are not being grandfathered.
Does anyone know, are the LOMA's no good either? Are they putting folks back into a flood plain after having been removed by a LOMA?

Dane,
Be cautious about the advice others have given here. Use of Section E or use of the simplified methods are likely not appropriate and very well may not provide for either the correct flood risk/insurance rating and subsequent rates charged, nor will it provide the owner with the correct understanding of risk he/she is encountering.
The use of Quick D is an engineering analysis. In California, where you practice, this is restricted to the practice of civil engineering.

I do a lot of these. It is my area of expertise. However, I am both a civil engineer and a land surveyor. There are a number of methods, information sources and steps one must go through to establish what the true BFE is. Sometimes it is relatively easy and fairly inexpensive, sometimes it can be very involved. Either way, it involves both risk assessment and the provider of the BFE assumes significant risk.
All too often, providers try and "help" the owner by trying to force a solution that meets the structure or site desires of the owner.
My advice to you is to consult with an engineer who specializes in hydraulic and hydrological studies. This is not a surveying exercise, it falls into the realm of a subset specialty of the practice of civil engineering.

Like I said, I do a lot of this kind of work and practice in your area. While I'm currently booked 6 months out for projects, I would be happy to discuss your project needs and go further in depth as to why some of the surveyor's advice given here by others is not well informed and incorrect.

I've done a few. More than a few actually. I'm not really sure what kind of info you're looking for but I can tell you this: You, as a surveyor, are not responsible for establishing a BFE. The information you provide FEMA will be used to establish a BFE by someone more qualified to do so. Fill that thing out to the best of your ability. Provide as much site information as you can.

> Dane,
> Be cautious about the advice others have given here. Use of Section E or use of the simplified methods are likely not appropriate and very well may not provide for either the correct flood risk/insurance rating and subsequent rates charged, nor will it provide the owner with the correct understanding of risk he/she is encountering.
> The use of Quick D is an engineering analysis. In California, where you practice, this is restricted to the practice of civil engineering.
>
> I do a lot of these. It is my area of expertise. However, I am both a civil engineer and a land surveyor. There are a number of methods, information sources and steps one must go through to establish what the true BFE is. Sometimes it is relatively easy and fairly inexpensive, sometimes it can be very involved. Either way, it involves both risk assessment and the provider of the BFE assumes significant risk.
> All too often, providers try and "help" the owner by trying to force a solution that meets the structure or site desires of the owner.
> My advice to you is to consult with an engineer who specializes in hydraulic and hydrological studies. This is not a surveying exercise, it falls into the realm of a subset specialty of the practice of civil engineering.
>
> Like I said, I do a lot of this kind of work and practice in your area. While I'm currently booked 6 months out for projects, I would be happy to discuss your project needs and go further in depth as to why some of the surveyor's advice given here by others is not well informed and incorrect.

Excellent advice that I completely agree with.

Establishing a BFE by flood study that will be incorporated by FEMA is not always the way to go, although it may be the norm in your area. But I agree that anyone, surveyor or engineer, that is in that business needs insurance to cover it. The thing about BFE's is any two equally qualified people can always arrive at slightly or greatly differing elevations. So, they are a prime target for lawsuits when flood damage occurs. Even for an elevation certificate with a published BFE I recommend the surveyor contract contain language suggesting that the client purchase flood insurance regardless of the outcome of the certificate. If you need a certificate, you are close enough to worry about it. But the liability is otherwise not any greater than any land survey. Liability is much greater if establishing a BFE for an entire area by flood study.

Many areas of the country surveyors are allowed to perform flood studies, and the FEMA regulations recognize that, and the surveying degree programs contain courses in hydraulics and hydrology. In our associate degree program it's covered in a course called environmental engineering. Personally I think it's land surveying and there's no one in a better position than land surveyors to perform these studies. Probably the most important part of the result is the correct measurement data.

I agree with Clearcut that this is not something to be undertaken by someone with no H&H experience. I'm not sure that always means an Engineer, however I completely agree that a detailed hydraulic study is going to provide the most accurate BFE and those should be done by an engineer. These get extremely expensive for the individual lot owner in a rural area and I think FEMA was trying to recognize that in both the manual and their Quick-2 program. A surveyor with no hydrology or hydraulic training would be both taking a risk and would also expend an inordinate amount of time trying to learn the process for one small job. In the end you would be sealing the work and you would need to document every facet of it. And, quite frankly, because Quick-2 is a "bare earth" model, it's going to most likely give you a similar floodplain as the map. That's how an unstudied map was done; by throwing a bare earth watershed discharge (not factoring in bridges culverts, roadways, other restrictions) into a quad map generated valley and stream. A detailed study factoring in all those items in will surely result in a more accurate, and in most cases lower, number. The problem again is if this type of study was too expensive for the mapping agency, will it be any less so for the individual? I guess what I'm saying is there is a reason for both the manual and the Quick-2 program. Read the manual in detail and don't undertake anything you have no experience or training in.

I've used this with an E.C. in support of a LOMA request

http://www.vtwaterquality.org/rivers/docs/nfip/rv_azonesurvey.pdf

"You, as a surveyor, are not responsible for establishing a BFE." That's dead on. BFEs should be in the domain of an engineer, and even if a surveyor does a great job based on the info he has, it is possible that you could be deemed as practicing outside of your area of expertise if there is a major flood and litigation breaks out. I think FEMA is pretty clear that a surveyor's responsibility in zone A is to seek out an "unpublished" BFE by a government agency, or fill out section E as a last resort.

I've used this with an E.C. in support of a LOMA request

That looks like a good service and is essentially asking for what Quick 2 would want except for the longitudinal stream grade. Probably quicker than trying to do it yourself. Still not as precise as a detailed study, but far less expensive too. Unless you get unfavorable results. With Flood insurance often going over $3K a year with the new rules, the decision to have an engineer do a detailed study may still be worthwhile. Still no guarantees though......Oh, the risks of living near the water!

In the case of Zone A ( No BFE), the FEMA guy told me to place in the Comments area of the EC the folowing, "No BFE is available from any local entity, so I am requesting FEMA to produce one". In most cases FEMA will come up with one and issue a LOMA is applicable.

John Harmon

>
> Many areas of the country surveyors are allowed to perform flood studies, and the FEMA regulations recognize that, and the surveying degree programs contain courses in hydraulics and hydrology. In our associate degree program it's covered in a course called environmental engineering. Personally I think it's land surveying and there's no one in a better position than land surveyors to perform these studies. Probably the most important part of the result is the correct measurement data.

The inquirer, Dane, is from California. Hydro studies are not part of California land surveying scope of practice. As for the rest of your comment as to who is best, or even adequately qualified, I'll just say that is a debate that would be interesting.

Well, I was not commenting on who might be "best". I'm sure engineers are just as capable of learning the process as surveyors.

I've used this with an E.C. in support of a LOMA request

Consideration should be given to the liability of the surveyor even though the computations are done by someone else. For example, a change in the cross section or and obstruction even in a very small area, can great affect the water surface profile. In addition, the vegetation density and type in the section area are subjective, and the people doing the calculation will be making some assumptions on the "n" value (roughness value) and restrictions. If the land floods and a lawsuit evolves, the interpretation of ground conditions by the surveyor may be brought into question, and thus the surveyor could become involved in the litigation. The person running the hydraulics computer program has no idea about the basin cross section other than what you give him.

It looks like they are trying to compute the flood level using only one section, and they are making some brave assumptions. One-dimensional flow, uniformity, n value from photos, no assessment of previous water marks or stream calibration, tailwater, backwater, etc. Risky. What is the significance of precision they are giving you the water surface profile?

I've used this with an E.C. in support of a LOMA request

You know Frank, I've thought that too since reading it the other day. It does seem overly simplistic. I agree on all your points. I don't know if FEMA would accept the liability for it or not. I'm guessing they would if they are offering it themselves. But I don't know how you could do any kind of valid open channel flow calculation without a mannings number, or at least a photo of the site to estimate it from.