If you look at satellite imagery it looks like you have very high terrain to the west of the runway. The water would be the primary area available for a climb back to obstacle clearance altitude. Looks like the MAP just routes you with sufficient time to climb to the MA altitude.
As Alexander already said in his answer, the turns over water are executed to gain enough altitude before turning back over the terrain.
(left: RNAV-A, right: RNAV approach chart).
The difference between the RNAV-A approach and the other two (RNAV and LOC) is the required minimum climb gradients for these two approaches. You find them at the bottom of the ...
The 300 m and 1 000 m tables you found are examples. For the actual radius for any aerodrome elevation you need to apply the formulae.
The radius is determined using the formulas in Section 2, Chapter 3, Turn area construction (...) The TAS is based on:
a) altitude: aerodrome elevation + 300 m (1 000 ft); and
b) temperature: ISA + 15°.
First is $R$...
The PBN manual is the place to start. In Section 5 on departure procedures it includes the following reference:
b. Leg type limitations. See Order 8260.46, paragraph 3-1-5 for
permissible leg types.
Also, all the TERPS requirements also apply, except where modified by the PBN manual.
There's usually no one rule that applies universally. It's about ...
In terminal areas with relatively low traffic levels, it may be simpler for ATC to let each flight climb or descend at their discretion, with verbal restrictions when an actual conflict appears. There is no point in trying to optimize these procedures because they're already pretty much optimal for the few flights that use them.
However, in busy terminal ...