A team of consultants found that even after repairs on the Sewerage & Water Board’s drainage system were well underway late last year, problems continued to plague the system and to hinder the city's ability to push water out of low-lying areas. 

The report, prepared over the fall by the international conglomerate Veolia and released Monday night, suggests that despite the emergency repairs and upgrades that have been going on since last summer's flooding, the system can do far less to pump water out of New Orleans than had been previously thought and that major problems with equipment threaten to further hamper operations.

The report found 170 critical problems with the drainage system at the end of November, including pumps that cannot move as much water as they are supposed to, clogged catch basins, drain lines and canals that slow the flow of water, and major deficiencies with nearly every electrical line tested.

It's not clear how many of those problems have been fixed since the first draft of the report was submitted. The consultants' assessments began at the end of August and went through the end of November, and repairs have been ongoing since then.

The S&WB did not provide additional information Tuesday in response to questions about the status of the drainage system.

But the report paints a picture of widespread problems that may be much more complex than just the number of pumps that can be turned on. The S&WB has used that and similar metrics — such as the amount of power that can be generated at its Carrollton plant — when providing updates on the status of the system.

Nearly 90 individual pieces of drainage equipment were “in the process of failing or have already failed” at the time of the report, and there are still no clear guidelines to determine how much capacity is needed to prevent flooding in the city, according to the report.

The S&WB is also still handling maintenance in an inefficient way, the report says.

The report was commissioned by the local agency in the aftermath of the Aug. 5 flood to give a comprehensive accounting of its maintenance problems.

Veolia's $5.8 million contract included preparing the report, installing 230 pieces of monitoring equipment throughout the system and developing software that lets S&WB officials monitor the status of pumps, turbines and other equipment in real time. 

The report focuses extensively on the 120 pumps that are the backbone of the drainage system. But only about 42 of those pumps could actually be tested to determine whether they could push as much water as the S&WB claimed.

Tests on other pumps either were considered unreliable, were scuttled when the pumps started exhibiting problems, or were impossible because the equipment was being repaired.

The evaluation “revealed numerous cases of severely deteriorated asset condition, diminished asset functional performance and inoperable assets which negatively impact system performance and compromise capability," according to the report.

The pumps subjected to Veolia’s testing, which theoretically make up about 54 percent of the total pumping capacity in the system, were actually able to move far less water than they were supposed to. The report estimates they can pump somewhere between 69 percent and 85 percent of the water they were designed to move.

And the problems are not limited to pumps that have gone without repairs. The report said one pump that was completely rebuilt by another contractor after last year's flooding was still operating at only 56 percent to 62 percent of its rated capacity.

Even with pumps that are working, the report raises serious concerns about the reliability of the lines that bring the electricity to power them. Of the 35 sets of underground cables that were evaluated, 30 failed the tests, and eight of those are considered in need of immediate replacement.

The report notes that those critically impaired lines were in the process of being repaired or replaced.

Beyond the pumps themselves, there are serious problems with the system designed to funnel water to the pumping stations. Based on samples of various parts of the drainage system, the report estimates that underground canals are 22 percent blocked, pipes are 27 percent blocked and open canals are 14 percent blocked.

The consultants also found that blockages were reducing the amount of water that could flow into catch basins by 16 percent, though the report suggests that work to clean the catch basins was still ongoing at the time.

Follow Jeff Adelson on Twitter, @jadelson.​