Backyard drainage problems / basement issues
I just bought a home with finished basement. Basement has a French Drain installed with 2 sump pumps. The past one month or so, the pumps runs almost constantly to keep up with the water entering the sump. During heavy rains, the water flows like a faucet in to the sump and the pumps kicks in every 30 seconds or so.
I have a small backyard, about 15 feet and beyond that is a small hill. During heavy rains, the water runs down from the hill like a stream and the backyard looks like a mini pond. I’m not sure if this is what causing so much water to enter the basement in to the sump. I was told that all neighbors have this issue and the water table itsself is very high in my area.
While the french drain and sump pumps are working as expected, I would like to figure out if there is anything else that could be done on the backyard to mitigate this issue (like an outside drain, dry-well, better landscaping etc)
If you can throw some ideas as to what could be done, that would be great !
Re: Backyard drainage problems / basement issues
Given the info listed in your post about a high water table, a finished basement, the need to keep the sumps going, the constant flow of water into the sumps/french drain, it would probably be best to consult the Yellow Pages under "Drainage Contractors" and have 1 or 2 contractors come over to take a 1st hand look at it & recommend the way to go on this; if you have any photos of this to upload email them to the site moderator, JM McDaniel.
Given that spring & early summer is usually the wettest time of the year in many parts of the U.S. do you live in an area that gets a lot of rain this time of year; what about late June & the summer months??? have you asked your neighbors yet what are the expected rain patterns in your area???
It looks like the previous owner has dealt with these issues previously, ergo the two sumps---when you say "french drain", do you mean that a trench has been dug in the cellar to collect the incoming water for the sumps???---a french drain usually refers to an exterior trench dug in the yard below basement/cellar grade with a passive 4" pitched drain pipe to collect the water.
There are many things to consider when designing an effective rain drainage runoff system that keeps water out of the cellar---from the sound of your post, the previous owner seems to have opted for a stop-gap arrangement, concentrating on the rainwater that has already entered the basement---that's why I think you should first start with an on-site evaluation by the drainage contractor on what to do next---always remember the first principle in dealing with yard water----it ALWAYS FLOWS DOWNHILL---even the SLIGHTEST PITCH one way or the other is enough to allow water to flow one way or another; this statement also implies that you have to conduct the runoff water FROM A HIGHER POINT, TO A LOWER POINT (notice the dry-well installations in the 2nd website below; they're all BELOW the house foundation; also note the house in the drawing is situated ABOVE street level; so basement water can be piped to the lower point in the street to be discharged directly into the street (if allowed by local code)---so the ideal condition on your property, is that your sump pumps/basement/french drain are presently sitting at a point that is slightly higher than some other point adjacent to your property (the street, for example) where you can easily discharge the runoff via gravity, or drain pipes slightly pitched toward the discharge end.
Another issue here is the soil content, and how well, or poorly it drains---if the soil has a lot of clay content, the rate of water drainage will be slow, sometimes non-existent; soils that have more of a sandy/gravelly content will drain more rapidly---it's not uncommon to see different areas of the same homestead that drain better than others, because the draining areas have sandy soil---you'll have to find the well-draining spots with a perc test by digging a 2-foot hole at various points, filling with water, & timing how many seconds/minutes it takes for the water to drain---if you find a low spot on your property that drains well, you can direct a dry well and 4" drainage pipes to that area, which may well solve your problem.
You mentioned a high water table in your yard & area, so one initial step might be to dig a covered test trench in the yard that goes down several feet below the basement sumps & french drain & see if it fills with water during a rainstorm---if it does, additional exterior french drains won't do you much good unless the water can be pumped to a discharge area in the street (allowed in some areas), or to a lower point somewhere else on your property; another possibility is that (hopefully not) your house foundation is sitting on the discharge point of a subterranean artesian spring flowing down from near the top of the hill---can you tell us if the street in front of your house is at a lower point than the basement floor??? And does your town allow runoff discharge into the street???? Are there any parts of your property that are at a lower point than the basement???
It's always a good idea to cellophane tape a small spirit level to the center edge piece of 2X4X8 and use this "level instrument" to go around to different parts of your yard to see of you have a negative pitch out to the street (for example) or to some point far away from the house foundation; also take a 30' heavy string with a spirit level attached, secure one end to the house foundation, and stretch the string around various points in the yard to determine the property low spots; you can then think of installing a drywell or to direct a buried 4" or 6" pitched plastic discharge pipe---plastic drain pipe, btw, along with most items mentioned in this post, are usually VERY LOW COST at HD/Lowe's, & this makes these projects amenable to a diy install.
You mention runoff rainwater "flowing down a hill out back & then toward the house"---in such cases this is a tailor-made situation for installing a CURTAIN DRAIN in such area (see website below); a curtain drain is a shallow gravel-filled trench with a perforated drain pipe at its bottom, installed along the high side outer perimeter of your property with the intention to capture the runoff coming down the hill & divert it into 4" or 6" pipe side channels on either side of the house hopefully to a lower point/drywell on your property, or into the street (if allowed); the 1st diagram of the curtain drain shows what looks like solid pipe---in actuality the 4" drainpipe used is PERFORATED with small holes pointing downward to collect the water as it rushes down the hill & diverts it to a lower point away from the house.
Sometimes the major problem is the runoff that's coming off your roof in a rainstorm that is not being collected by an effective roof gutter system, with good, non-leaking downspouts, & downspout extenders to get the runoff away from the foundation, or buried catch basins going into 4" plastic drainage pipes that direct the runoff to a distant location away from the house.
One of the sites below lists a price for drywells, but there is no need to purchase anything; drywells can be made of discarded perforated large steel/plastic barrels, or simply piled discarded rocks/broken bricks thrown into a dug hole in the yard.
Also Google such keyword phrases as "improving yard drainage", "soggy yard", "drywell construction", "eliminating basement water", "wet basement solutions", etc.
Last edited by brewster; 06-15-2013 at 01:05 PM.
Re: Backyard drainage problems / basement issues
Thanks for your detailed response. Let me try to answer the questions as much as I know. I do have some photos that I will send to the moderator.
- I live in Shrewsbury, MA and it is raining very heavily for the past few weeks ( about 5+ inches in June alone )
- Drain was installed inside the basement which then drains in to sump pit with 2 pumps (primary+backup)
- I don't see any drain installed outside the home as far as I can tell. I will ask my neighbor about this.
- Homes opposite to me don't have this problem, they don't even have sump pits installed and the are in lower
level than my home. this is what baffles me.
- My yard slopes towards the street with a storm drain right next to my road. As of today, all the run off from the
back hill goes to street and in to a street storm drain anyway due to the nature of slope in my area.
- I have observed that some of neighbors in my side have built a small wall right next to the base of the hill and
I'm assuming may have also installed a drain to supplement it
As you mentioned, I'm suspecting the issue is mainly due to very high water table . There is a lake about 0.5 miles away from home that is actually at a higher elevation than my area and also there is Quinsigamond river that is about less than half mile but in a lower elevation from our area.
If the amount of water entering is due to high water table, what kind of work would be needed to prevent so much water entering the basement ? I heard outside treatment are very expensive and that is what I'm worried about.
Thanks for your time and consideration !
Re: Backyard drainage problems / basement issues
Would love to see any photos you have of the sumps, french drain & yard layout, as it's hard to visualize over the internet about a specific location, and as stated previously, it would no doubt take a pro in drainage issues to come out to your house to make an on-site evaluation of the drainage system you have now, and if any modifications would improve things.
Yes, I also live in New England & the area has received an unusually large amount of rain this June---all the streams in southern New England are swollen & at flood stage, and ordinarily the coming months have very little rainfall, which should help things.
An encouraging thing I noticed in your last post (if I read it right) is that your property is at least slightly higher than the street, and if you can capture all or nearly all of the water coming onto your property during high water events into buried 4" or 6" drain pipe & have the discharge point directly onto the lower point of the street, this would be the ideal solution, & you wouldn't have to burn any electricity by using the sumps all the time.
The fact that your nearby neighbors don't have basement water is also an encouraging sign.
Have you called any drainage contractors yet to get an on-site evaluation & recommendation of which way to go ???