I made some research trying to find all estimates of Hamas'
tunnels. This table summarizes it:
Length |
Depth |
Year |
Citation |
|
65 feet (20 m) |
2014 |
no cite |
500 km |
|
2021 |
Yahya Sinwar7 |
300 km |
|
2021 |
"Israeli army"1 |
300 miles (500 km) |
|
2021 |
"Israeli military"8 |
|
15 - 60 m |
2023 |
"experts"1 |
200 miles (300 km) |
|
2023 |
"reports"2 |
|
200 feet (60 m) |
2023 |
"Some Israeli military experts"2 |
300 miles (500 km) |
|
2023 |
"Hamas claims"3 |
500 km |
|
2023 |
"Hamas meanwhile claimed"4 |
|
30 m |
2023 |
"are believed to be"4 |
|
45 m |
2023 |
"There are claims"5 |
500 km |
70 m |
2023 |
"is thought to be"6 |
In brackets I have converted the estimates to SI units and rounded to
one significant digit. Some sources estimate average or maximum depth
and others estimate total length. The source column shows to whom the
secondary source (the article itself) credits the estimate to. For
example, the article ‘Very risky’: Israel faces months-long campaign
against Hamas Gaza
tunnels
cites "experts estimating a depth between a range of 15 to 60
metres" but doesn't specify who these experts are.
There is a lack of authoritative primary sources. The second source
either uses passive language ("is thought to be"), indicating that the
journalist just "googled it", or cites unnamed experts,
or cites the leader of Hamas Yahya Sinwar who in 2021 claimed that
Hamas possessed 500 km of
tunnels.
Here are my conclusions of the evidence. Feel free to draw your own:
Unless you trust unnamed Israeli military sources or Yahya Sinwar's
word, no credible evidence suggests that the total length of all
Hamas tunnels approaches the hundreds of kilometers range. For
comparison, Paris' metro is 214
km-long and its sewer system is 2,100 km-long.
Same goes for the depth. Deep tunnels face many technical
difficulties such as groundwater infiltration, ventilation,
lighting, and earth pressure. Gaza's soil is made of sediment of
clay and sand so tunnels have to be reinforced with concrete to
prevent them from collapsing. Deeper tunnels face more pressure and
need more reinforcement.