I found the "dam!"

The Al Mezan Center for Human Rights also blames Israel for supposedly opening up a dam in order to flood poor Gazans during torrential rains last week:

For the second time in the past ten years, at approximately 6pm on Monday 18 January 2010, Israel opened the floodgates of one of the dams in the Gaza Valley, which flows into Gaza from the east. As a result, dozens of Palestinian houses and properties were damaged. Israel built this floodgate to prevent the rainwater's natural flow into Gaza, depriving the Gaza aquifer from its main natural source of underground water.

Here we see how trustworthy this prestigious "human rights" organization is. Since it is the second time it happened, it must tell us about the first:

A similar situation had occurred when the so-called Nahal Oz dam suddenly collapsed nine years ago, on 26 March 2001. Hundreds of donams of agricultural lands; chicken and cow farms; and rural houses were damaged.

It seems we found a dam, in Nahal Oz! Yet the news stories from that date don't quite call it a dam - it is a reservoir:

A special committee has been established to investigate the bursting of a reservoir near Kibbutz Nahal Oz yesterday which caused extensive flooding and the loss of over 3 million cubic meters of irrigation water. The purified sewage water piped in from the Dan region treatment plant flooded vast tracts of arable land and swamped low-lying fields of Palestinian farmers in the nearby Gaza strip.

So we see that Al Mezan is lying in the first paragraph when they claim that Israel opened the floodgates in 2001; it is lying when they said that Israel opened a dam in 2010, it is lying when it says that the purpose of the "dam" is to deprive Gazans of rainwater (the water in the reservoir is piped in as purified sewage water for Israeli agriculture.) But it means that we can now find that picture of the "dam" we were looking for, even if it was never opened - and, indeed, if it is unlikely to even have a mechanism for opening.