Who owns the pipe? It would be easier to go inside the pipe to plug the holes. If the pipe is moving (Settling), this should be done soon. If the pipe comes apart during a storm event it could wash away a lot of soil and buildings.

The ownership of the line once it leaves the highway ROW is that of the property owner. The line materials were purchased by my father & the county installed with 'free' chain-gang labor back in the 60's. You get what you pay for......

The line, now that I have dug up a separated joint, is 36" and not the 48" I thought. I agree sealing from inside is the best way to go but not down 150 lineal ft of 36" from nearest manholes.

So far, I have used lean mortor on joints & have tried some of the canned expanding foam. Most open joints seem ~2"-4"; not a lot to seal but a chore to get to it with just a shovel. Luckily the tops are not more than 2' below grade.

We used to send a guy down the pipe on a mechanic's crawler, pushing a bucket of mortar. The line is probably 8' pipes But you would have to abide by all the OSHA reg.s. I would look at trying to give this line back to the County. Get all the 'owners' of the line together and petition the County to take it over.
The other best solution may be to line it with a CIPP liner. This  would be spendy for one person to pay for.

I am facing the same problem. Only I am designing the repairs for a town. We are going to line the pipes. The best way I have found is to tv inspect the lines to determine the amount of deterioration.

Then have the pipes jet cleaned if possible. If there is too much damage this will just blow the pipe apart. I am assuming that if it was installed in the 1960's it is cmp pipe.

After it is cleaned the process involves sending a "balloon" down the pie and injecting plastic (?) sealer onto the walls of the pipe. The balloon is dragged behind the sprayer and pushes the plastic into the grooves of the pipe. This will give it a smooth finish similar to hdpe.

I would check the deed that was filed for this installation. In new jersey, the towns are usually required to maintain their respective drainage systems. This includes the maintenance and repairs.

I hope this helps.

You could do a more permanent job by lining the pipe by the Cured-in Place Pipe method but for a homeowner this is real spendy.

My county will assume maintenance of the pipe if you grant them an easement.  You might approach your county about granting them a 10'-15' wide stormwater easement if they agree to maintain the pipe. The downside of the easement, is that they have a tendancy to grow larger and get other utilities or even a roadway.

You also might approach the upstream landowner and request that he maintain or pay for the fix of the pipes.  You might encourage him by allowing the pipe flow capacity to be reduced via benign neglect.  I do not know if this is really legal as he may some riparian rights to the pipe.

I really like dicksewerrat's proposal about mechanic's crawler pushing a bucket of mortar.  You might add a good flashlight or a miner/caver helmet with a light.  300 Lineal feet is about 35 joints.  You probably could do a joint every 20 minutes for a total of about 12 hours of work.  Then again , I like caving and small spaces do not bother me.  Carry a cell phone for security and have a spotter near by.  I surely would not dig up 35 joints.  Sealing from the inside could probably be done for 1 sixty pound bag of mortar mix per joint and at $2.50 per bag, under $100 in materials and no backbreaking labor.  You could always hire a wiry guy to ride the crawler into the pipes, it would add to the expense, maybe another $100 or so.

Clifford H Laubstein
FL PE 58662

Working within a 36" pipe....be very very careful.  I knew of a contractor that was sealing and mortaring 36" pipe.  The pipe was stormwater and had manholes every 400 meters or so.  The poor soul was about 3/4 of the distance upstream (inside the pipe) when a flash (intense) rainstorm hit the coolection area in the City.  Bottom line was that the guy guy drowned due to the fact that nobody really paid too much attention because little rain fell in their proximity.  They did not have him harnessed and were not able to retrieve him fast enough.  Not to put a downer on it all, just be careful.  Also, ensure that the line is purged with a fresh air source.

One troubling issue though is how did the pipe end up oon your property anyway?  What is it draining?  Municipal? Private?  If they do not have an easement or right-of-way caveats, then that line is likely in trespass and damages (sinkholes) resulting from the water flowing through the channel may be recoverable in a civil action.  If it is municipal, it is probably easier to convince them to repair the line.

KRS Services
www.krs-services.com

I would not send anyone into a 36" storm pipe...I think that's begging for trouble.  Donating the drainage and an easement to your local jurisdiction may be the best approach for you.  They may be able to rehabilitate the pipe w/out ripping the whole thing up.  Options include sliplining the existing pipe with a plastic liner (HDPE) or a technique called "pipe bursting" in which a new pipe is pulled through the existing pipe.  But, if it's the jurisdiction's pipe, let them worry about it (but you may have to lobby hard to get them to act soon).

Before you do ANY changes to the pipe, other than simple repairs, you'd better have a professional engineer evaluate the design hydraulic capacity of the pipe and the capacity after you do your work. (i.e., don't change the inside diameter, internal roughness, or anything that could reduce (or increase) the flow through the pipe..it may not be designed for increased flow downstream.  Decreasing the flow upstream could result in flooding of your upstream neighbors.  Either way, you may be liable for damages.)

Again, the best approach for you is the donation to the local jurisdiction.  If the pipe drains only private property, the jurisdiction probably won't want the pipe.  In that case, you'd better get with the neighbors upstream that contribute to the drainage and get their $$$$ support.

Good luck-drainage issues can get messy.