The most common and most likely answer to this crossword clue is the 7 letter word SANDBAG
S
A
N
D
B
A
G
More clues leading to the result SANDBAG
- Polish to get the sack for blockage
- Unexpectedly attack son with net
- Band trained to go in to drop flood defence
- Bad snag ruined element of flood protection
- Attack weapon used by Thatcher to start afresh
- Surveyor’s beginning with land that prevents flooding
- Some ballast initially, a good defence against flooding
- Possible ballast to drop, with balloon initially secured?
- Second temporary Worthing home not hard — quite a soft pad
- Son replaces front of portable accessory that checks tide
Buddy explains!

The straight part
We know that "element of flood protection" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case element of flood protection = sandbag.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SANDBAG mean?
SANDBAG noun- A sturdy sack filled with sand, generally used in large numbers to make defensive walls against flooding, bullets, or shrapnel.
- A small bag filled with sand and used as a cudgel.
- An engraver's leather cushion, etc.
- A deceptive play whereby a player with a strong hand bets weakly or passively.
- To construct a barrier of sandbags around.
- To strike someone with a sandbag or other object to disable or render unconscious.
- To conceal or misrepresent one's true position, potential, or intent in order to gain an advantage.