Dewatering Permit? 2

[diggerman]

Recently, there was an employee who persisted that the contractor could not de-water an area unless he applied for a dewatering permit. Is there such a thing? The project already had an existing NPDES permit posted. I thought that the NPDES Permit umbrella's all de-watering; provided that it is done correctly according to the rules. A little input please.

 

[bimr]

If the groundwater is contaminated, dicharge to surface water may cause the spread of pollution. For that reason permits are required for dewatering activities.

Dewatering activities are regulated by various state and local laws and regulations. You need to check with the local authority having jurisdiction.

Here is an example:

http://www.nj.gov/dep/watersupply/bwa-002.pdf

 

[diggerman]

It is a simple dewatering operation. Moving water from undergound to an adjacent area temporarily so the contractor can do some excavation. No contamination at all.
Anyways, I've never heard of holding the contractor up for weeks on waiting for a dewatering permit, thats my point.
Maybe there is. I just hate contacting local agencies! I thought that having a NPDES permit covered dewatering. More input is appreciated! Thanks

 

[cvg]

NPDES has very little to do with dewatering.

yes, a de-watering permit from the state is probably required. Typically this is not a big deal assuming you are not removing large quantities of water. The contractor may be required to keep records of the pumping and you would submit those to the state for their records. If you are installing wells to dewater, they will have to be registered also.

It shouldn't require weeks to get a permit. (although with the recent budget issues, hard to say how many employees are working at the department of water resources these days)

 

[civilman72]

"NPDES permit" I believe is a bit vague. You should have some kind of permit from the State, but more than likely this is a Stormwater Management permit, which deals with erosion and sediment control, and is definitely a separate permit than a dewatering permit.

If this is truly a small amount of dewatering over a short time period, and you can place it in a hole adjacent to the excavation and allow the water to perc back to the soil or evaporate, then you probably "should" get a permit, but for a small project, you probably can get away without one. However, if you are discharging ANY amount of water to a storm sewer or adjacent stream then you definitely need a dewatering permit.

 

[diggerman]

CIVILMAN72

THANKS A BUNCH.

 

[fattdad]

consider that dewatering has the potential to affect soil stresses below adjacent properties. As such, depending on the local soils, your simple, low-volume dewatering program could lead to induced settlements. It would not surprise me to learn that highly urbanized areas have oversight on dewatering operations to protect their own utilities and third-party claims.

to the best of my knowledge there is no widely-held requirement for dewatering permits, but at the local level there could be. . . .

f-d

¡papá gordo ain’t no madre flaca!

 

[diggerman]

Good point f-d. Here in Florida recently(last week actually) there were several sinkholes activated. Many home owners blamed nearby orangegrove owners for overwatering thier trees during the freeze to prevent destroying the produce. Taking water away from the soil actually decreases the stresses holding the soils together resulting in failure? I guess there's some GEOTECH involved here! AH HA it all comes together now.

 

[fattdad]

Imagine standing in a pool during the heat of the Florida summer. You're nice and cool and holding your girlfriend. She's light as a feather. Some stupid kid pulls the plug out of the pool. The water drops. All of the sudden, your girlfiend is as heavy as a whale.

When you dewater a site, the lowering of the water table removes bouyancy. This increases the state of stress on the underlying soils (i.e., the soils that are below the dewatering limits).

Hope this helps.

f-d

¡papá gordo ain’t no madre flaca!

 

[Sasmo12]

If the project is in fact in Florida, there is a dewatering permit required. The type will likely depend on the requirements of the Water Management District the project is in. Typically, though you will need either a "No-Notice" Permit, a "Standard General" Permit, or an "Individual" Permit.

Which you require is determined by a number of things including, but not necessarily limited to: proximity to a wetland, State Waters, or other waters of the State; depth of dewatering; proximity to public water sources (supply wells for treatment plants); volume of dewatering; length of time dewatering will occur; etc.

You also have to have a dewatering permit if your project is within the boundaries of a Master Dewatering Permit. This can be the case if you single parcel project is within a master planned community.

If not in Florida, then I would find the water management district or equivalent agency, and find out their regulations. By the way, while the NPDES permit is usually not related to dewatering, you can violate your NPDES permit with bad dewatering practices.

Hope this helps,
Sasmo12

 

[darthsoilsguy2]

i can see it being an issue if the dewatering is being done immediately downgradient of a delineated wetland whose protection was incorporated into the state issued permit. Also, the extent of the operation plays a factor.

it happens all the time though. dewatering usually comes with headaches that start with a couple weeks lead time ahead of the dewatering operation. i figure people wil eagerly look the other way hoping there aren't any other unforeseen delays.

 

[diggerman]

The General NPDES permit I think covers the dewatering provided that all discharges are dealt with accordingly.
If you file for a NPDES permit for a certain project
it covers dewatering. IT IS NOT LIMITED TO EROSION CONTROL AND SEDIMENT CONTROL.

 

[diggerman]

CVG-

The General NPDES has alot to do with dewatering. You may want to do some more research.

 

[Ltwine]

Permit, or no permit, just be prudent before dewatering. A leason learned back home:

A 4 story residential in the conjested city setting. A intense rain storm occurred shortly after completion of the basement excavation and flood the open pit. The contractor started to pump the water out with sumps working faster then the dimished rain fall and seepage infiltration from the soaked pit walls. On the next day, he had made the pit near dry with some thing extra hanging on one edge - an adjacent 4 story building, which had broke the auger pile shoring, had sinked, tilted, and slided a few feet into the pit. After lengthy legal process, the contractor had to build two buildings with large amount of fines and compensations.

The entire city was on sediment of an ancient lake, there were efforts to control settlement by replendish the lowered groundwater due to excessive pumping. A permit wasn't required for the size of project, But...

 

[cvg]

diggerman
of course, during your dewatering operations as with all construction, you have to follow the requirements of the SWPPP to meet the intent of the NPDES. However NPDES was not initiated to control dewatering operations, but for much broader issues of water pollution caused by a multitude of activities. Primary one us engineers are concerned with are construction activities which include excavation and the release of sediment to waters of the US. So, by all means you must submit a NOI, prepare a SWPPP, conduct your activities using BMP's and follow all the requirements of your states NPDES permit. In addition, you need to follow the state's requirements for dewatering which probably means obtain a dewatering permit. This means protect your property from subsidence, protect adjacent properties and protect receiving waters from pollution caused by your dewatering activities.

 

[Drumchaser]

To my knowledge we have not encountered having to secure additional permitting for this type of activity.
That being said we have not dewatered in congested/urban areas.
I would agree with cvg on the points he made with regard to NPDES, as for the subsidence; that sounds prudent as well.

I would contact a local/regional company that specializes in dewatering (which can be highly specialized equipt., and very skill oriented)...they should be able to give you a cost breakdown that should include any fees, permits, bonding and or surety requirements for said work.

 

[diggerman]

I definately concur with CVG and all you guys. It appears that dewatering is/has become an issue lately since last I was in the buisness. It's very tempting to have/apply for an NPDES permit and think your covered but your not. However other agencies are involved. Too many permits, not enough time. I just hate holding the contractor up on waiting for an arrival of a dewatering permit. However, that is where planning ahead of time must come in I guess. Welcome to the world of Project Management.

 

[darthsoilsguy2]

the npdes permit certainly should cover the discharge side though.

 

[concretemasonry]

It the land is in or adjacent to a wetlands area there are many other agencies that get involved. They are especially concerned with the discharge and chance of an accidental accident/construction error and leakage and the consequences.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[StackNPac]

Depending on which water management district you are in, there are thresholds (in GPD) that determine if you need a dewatering permit from them. Also, if you discharge to state waters there is a generic FDEP dewatering permit that very few people know about or follow. You can find it here:

http://www.dep.state.fl.us/water/wastewater/iw/docs/62-621.300_2.pdf