Yes, even I noticed the increase of water pressure in the last 24 hours. However I reluctantly have to agree with JB that PPWSA have always been one of the best run services in Cambodia.
But also have to disagree with your explanation here,,,,,
Quote,,
I need to explain the process of pipeline construction to explain why this happens. Due to the nature of PP's ground (silty clay, high water table), workers often have to install pipes in deep trenches in presence of groundwater. It is not always possible to properly dewater the trenches without causing a risk of collapse, either of the trench, or of the adjacent ground (usually houses or roads). Sometimes the trench is dry, but following backfill, groundwater comes back and can enter the pipeline under construction through one of its ends. Finally, during intense storms, runoff water enters the trenches and therefore the pipe. It is extremely difficult to complete a pipe construction without ingress of groundwater mixed with soil, aka mud. This photo will give you an idea of the pipe laying conditions.

If this were the case there would never ever be any construction carried out below sea level.

This video deals with entirely different works.
These cofferdams are used for local, heavy works (e.g. bridge pile) that can take months or years to complete. For example, we are currently building a water intake in the Mekong River using a fully watertight cofferdam. In such cases, it makes sense to invest several months and a lot of money in the construction of a cofferdam, which includes interlocked sheetpiles, heavy bracing, a reinforced concrete plug at the bottom (something not mentioned in the video) and sometimes even foundations.

All those things are impossible for pipeline construction, which is a rolling process: the trench is excavated in the morning, then the pipes are laid, the trench is backfilled in the evening - and the whole thing moves on at a rate of 2 to 3 pipes a day, which is (depending on the diameter) 12 to 25 m/day. We mostly work on the side of congested roads or boulevards and are asked to limit the disturbance of traffic, so we have little space for heavy machinery. Driving sheetpiles either by hammer or vibrator is extremely slow and creates a lot of nuisance, and potentially damage, to the houses nearby so we tend to use trench boxes, as shown on the photo of my previous post; those are obviously not water tight. There is obviously no time to pour a concrete slab at the bottom of the trench before laying pipes - otherwise what took us 2 years to construct would have taken 4 or 5.

Therefore, we have to resort to trench dewatering, as explained in the video, which is sometimes tricky because if you pump too fast, you risk to suck some soil, create cavities and cause some collapsing. That's why works sites can be muddy and, despite all precautions taken, we cannot guarantee that no muddy water enters the pipe under construction.

Next Question. Is a '' pig '' put through the line to help clear residue like mud stuck to the walls of the pipe ?

One thing I don't understand: we have the Mekong river, the 7th or 9th biggest river in the world, (depending on your criteria) close by.

Why the water shortage? I don't mean when they are installing pipes, I mean before that. And why does it take so long to build a treatment plant when condos are built in under a year or two?

PPWSA should be funded by the government, isn't water a basic facility that people pay taxes for?

If the pumps are the problem, can they not install bigger ones?

Tootsfriend wrote: ↑Sun Apr 30, 2023 2:48 am Next Question. Is a '' pig '' put through the line to help clear residue like mud stuck to the walls of the pipe ?

That's an excellent question. Yes, it would do the job, but we are not equipped for that. Pigs require entry and exit "stations", which are simple for small diameters (like in this video) but fairly complex and expensive for larger diameters like the ones we have in the city. Besides, you need to be able to accurately control pressure to set the pig in motion, which is not always the case in a meshed network like ours.

schlarry wrote: ↑Sun Apr 30, 2023 3:27 am One thing I don't understand: we have the Mekong river, the 7th or 9th biggest river in the world, (depending on your criteria) close by.

Why the water shortage? I don't mean when they are installing pipes, I mean before that. And why does it take so long to build a treatment plant when condos are built in under a year or two?

PPWSA should be funded by the government, isn't water a basic facility that people pay taxes for?

If the pumps are the problem, can they not install bigger ones?

Installing bigger pumps isn't that easy.

They'd have install bigger transformers and bigger panels for the pumps, then before they can even turn them on they'd need to get larger pipes.

Darkcel wrote: ↑Sun Apr 30, 2023 9:23 am

schlarry wrote: ↑Sun Apr 30, 2023 3:27 am One thing I don't understand: we have the Mekong river, the 7th or 9th biggest river in the world, (depending on your criteria) close by.

Why the water shortage? I don't mean when they are installing pipes, I mean before that. And why does it take so long to build a treatment plant when condos are built in under a year or two?

PPWSA should be funded by the government, isn't water a basic facility that people pay taxes for?

If the pumps are the problem, can they not install bigger ones?

Installing bigger pumps isn't that easy.

They'd have install bigger transformers and bigger panels for the pumps, then before they can even turn them on they'd need to get larger pipes.

I think we also have to remember that 20 years ago most buildings in PP were only 3 or 4 stories high. If bigger pumps and higher pressures are used most of the older water pipes would not withstand the pressure.

Tootsfriend wrote: ↑Sun Apr 30, 2023 9:50 am

Darkcel wrote: ↑Sun Apr 30, 2023 9:23 am

schlarry wrote: ↑Sun Apr 30, 2023 3:27 am One thing I don't understand: we have the Mekong river, the 7th or 9th biggest river in the world, (depending on your criteria) close by.

Why the water shortage? I don't mean when they are installing pipes, I mean before that. And why does it take so long to build a treatment plant when condos are built in under a year or two?

PPWSA should be funded by the government, isn't water a basic facility that people pay taxes for?

If the pumps are the problem, can they not install bigger ones?

Installing bigger pumps isn't that easy.

They'd have install bigger transformers and bigger panels for the pumps, then before they can even turn them on they'd need to get larger pipes.

I think we also have to remember that 20 years ago most buildings in PP were only 3 or 4 stories high. If bigger pumps and higher pressures are used most of the older water pipes would not withstand the pressure.

Exactly, they'd need additional booster pumps with everything else being upgraded.

It wouldn't exactly be cheap either, seeing as how these pumphouses are huge buildings holding 2 to 4 pumps

schlarry wrote: ↑Sun Apr 30, 2023 3:27 am Why the water shortage?

Please refer to my previous post on the subject (p3 of this thread)

And why does it take so long to build a treatment plant when condos are built in under a year or two?

Short answer: because water production & transmission is slightly more complex than a condo
Long answer:
- your 2-years construction duration does not account for the preparation time: design, financing, arrangements with contractors, obtaining approvals etc. which can take as long as the construction itself
- a condo is built on a single site and involves mostly civil works, followed by architectural/finishing works. Water production, conversely, involves large and sometimes very complex works on multiple sites: a water intake in a river, a water treatment plant on another site, a pipe junction between both, and a transmission & distribution network throughout the city. After completion of the civil works, unlike in a condo, a crazy amount of mechanical and electrical equipment has to be installed and tested before the facilities can come live: this necessarily takes more time than completing a condo.
- We completed the Bakheng treatment plant in 3 years, which is not that long considering all of the above. The project was initiated in 2015-2016, so it is actually its preparation (studies, preliminary design, impact studies, permits of all kinds, financing, tendering) that takes most time.
- There is currently a second stage being built that will come live by the end of this year, and 3 engineering teams working on 5 more water supply projects. We didn't wait for the shortage to take action!

PPWSA should be funded by the government, isn't water a basic facility that people pay taxes for?

No, PPWSA makes money out of the water sales, and is not funded by taxes.
The government helps insofar as it borrows money to fund the construction projects, and retrocedes the proceeds of the loans to PPWSA. Obviously, PPWSA has to pay back.

If the pumps are the problem, can they not install bigger ones?

Pumps are only one element of integrated facilities sized for a fixed nominal capacity. Think of it as a chain: you don't increase its capacity by replacing only one link.