Drainage Consultant

[LivinLOS]

I have 5 rai of good land I will be building on..

The land is almost totally flat.. And with these rains (and a huge build up of plant life / grasses over the wet season) has become soggy with surface water. This isnt flood, the water table which is visible as nearby plots have water holes for agriculture) is way under the land level. This isnt rice land or reclaimed low lieing land at all. But I would like to speak with a professional with some knowledge, now while its wet, before I start any plans and building.

My wifes instant reaction is we need to raise the land, however I think thats not good advice as 1) we are above the water table 2) we are above nearby plots anyway 3) this isnt flooding issues its drainage issues, I know that sounds the same but it sort of isnt. Raising the land over all 5 rai brings the same problem 1 meter higher. This is about clearing surface water off the plot and creating a drainage solution.

I was thinking some intelligently placed trenches, with rough aggregate to create drain channels, leading to the (and off of) the lowest part of the land. Even creating a pond area to drain too if I had to.

Does anyone know anyone with this kind of skills and knowledge ?? A ground worker or landscaper ??

Edited October 9, 2011 by LivinLOS

[Lobo4819]

In a past life I did some consulting work such as you are talking about and also did remediation work with houses that had suffered water damage. Without even seeing your land, one comment would be to dig a pond in one corner of the property, and let gravity (the easiest solution) take the water there. Plus, you could have some nice fish. The biggest problem around here is "where does the water go?" If it is just ponding and not flooding, and you are sufficiently above grade (from your description) not to worry about flooding, creating the pond about 6-8 feet deep on the downward slope (if there is one) of the property would be the most practical and cost-effective. It may get low or dry out in the dry season, but it doesn't sound as if that would bother you.

[Diablo Bob]

You need a civil engineer. If your property is essentially flat you will need to establish a grade away from your intended building location. This would necessitate the addition of fill material for a building pad.

If you are contemplating putting in a few ponds, these cound be used to develop the required fill for your building pad and serve the purpose of retaining the rainwater......

Most civil engineers could develop such a plan. In conjuction with a landscape architect they could make these modifications look natural.

[Lobo4819]

Also, beware the use of new fill to build on. Proper compaction by mechanical means, or time, is necessary to prevent the headaches of settlement. Finally, invest in wide, deep footers for your foundation.

[LivinLOS]

In a past life I did some consulting work such as you are talking about and also did remediation work with houses that had suffered water damage. Without even seeing your land, one comment would be to dig a pond in one corner of the property, and let gravity (the easiest solution) take the water there. Plus, you could have some nice fish. The biggest problem around here is "where does the water go?" If it is just ponding and not flooding, and you are sufficiently above grade (from your description) not to worry about flooding, creating the pond about 6-8 feet deep on the downward slope (if there is one) of the property would be the most practical and cost-effective. It may get low or dry out in the dry season, but it doesn't sound as if that would bother you.

A pond in one corner is one of my plans.. Getting surface water to the pond location is what a decent landscaper might be able to suggest..

There is a very very slight grade, and this brings it to the corner of the plot, where neighboring farmland is lower, so I really think with the right drainage work this is solveable.. This isnt liek inches of standing water, its just 'soggy ground' which is probably made worse beacuse we left if fallow this summer and WOW did the grass and bush life go crazy.

We just had this cut so theres like few inches of hacked down grass, acting as a giant sponge, holding water at the4 surface.. But I would like it looked at by a pro.. Just finding real pros here isnt always easy.

You need a civil engineer. If your property is essentially flat you will need to establish a grade away from your intended building location. This would necessitate the addition of fill material for a building pad.

If you are contemplating putting in a few ponds, these cound be used to develop the required fill for your building pad and serve the purpose of retaining the rainwater......

Most civil engineers could develop such a plan. In conjuction with a landscape architect they could make these modifications look natural.

Really trying to avoid fill for a few reasons.. Mainly I dont think its necessary, secondly as it would possibly delay building on it..

Also, beware the use of new fill to build on. Proper compaction by mechanical means, or time, is necessary to prevent the headaches of settlement. Finally, invest in wide, deep footers for your foundation.

I have lived in million dollar villas here, where they were falling apart, its my intention to really overbuild on the footings and foundations.

[Dante99]

Drive pilings in and put the foundation on them. That is the best way to get it firm.

With 5 rai of land, the drainage problem could be a bit difficult because the drain or pipe requires a slope and if the distance is long, the total drop may be large requiring a very deep outlet which may not be possible. (5cm/meter slope for 40 meters gives you a drop of 2 meters, you might get by with less than 5cm/meter but ...) You may be better off having a civil engineer design the drainage rather than a landscaper.

[LivinLOS]

Drive pilings in and put the foundation on them. That is the best way to get it firm.

With 5 rai of land, the drainage problem could be a bit difficult because the drain or pipe requires a slope and if the distance is long, the total drop may be large requiring a very deep outlet which may not be possible. (5cm/meter slope for 40 meters gives you a drop of 2 meters, you might get by with less than 5cm/meter but ...) You may be better off having a civil engineer design the drainage rather than a landscaper.

So does anyone know a decent civil engineer who can look at this up here ??

One who I can just be advised by, to then build into my designs and plans. I may be making a mountain out of a molehill, after all I am bothered by some wet ground, when half the town is 1m deep underwater (thats when I last went and checked it, the only time its been wet).

[Dante99]

Drive pilings in and put the foundation on them. That is the best way to get it firm.

With 5 rai of land, the drainage problem could be a bit difficult because the drain or pipe requires a slope and if the distance is long, the total drop may be large requiring a very deep outlet which may not be possible. (5cm/meter slope for 40 meters gives you a drop of 2 meters, you might get by with less than 5cm/meter but ...) You may be better off having a civil engineer design the drainage rather than a landscaper.

So does anyone know a decent civil engineer who can look at this up here ??

One who I can just be advised by, to then build into my designs and plans. I may be making a mountain out of a molehill, after all I am bothered by some wet ground, when half the town is 1m deep underwater (thats when I last went and checked it, the only time its been wet).

When I want to find a skilled person to do anything related to construction, I just go to a place where they are building good quality homes, look around and if I like what I see, I ask the contractor or sub contractors for the name of the guy that did it and his phone number. Sorry, I can not provide you a name because I have never needed a civil engineer.

Frankly, if you are going to do the design, all you need to do is find the elevations at various spots on your land and go from there. You can get the relative elevations with a tape measure, some stakes and a plastic hose filled with water. Nobody can give you much good advice without knowing the relative elevations anyway.

[LivinLOS]

I doubt theres 30cm over the whole plot.. In fact I doubt its 15 but say 30 for a bit of wiggle room.

I will see if the architect I have been recommended has anyone.. Just wary of the whole kickback scene and as he knows the scope of what I want to build probably have a big ticket target painted firmly on any deal that goes that way.