Determining, determinative, determinant...

Hi!
A friend of mine asked me to translate a small text from Portuguese to English, and in the middle of the process, I discovered that the word "determinant" cannot be used as a synonym of "crucial/decisive". :-o

Now, the sentence I have doesn't "sound" good: "Cherishing our culture and preserving our heritage are determining (adj?) to elevate the good image of the region".

Moreover, does this sentence sound right? "The management of water resources is a decisive factor so as to guarantee full access to water to the populations." Or should it be "The management of water resources is a decisive factor so as to guarantee the populations full access to water."?

Appreciate any help!

1 It doesn't work- I'd use vital to elevating
2 How about 'decisive factor in ensuring the whole population has full access to water'?

Thank you very much for your help and suggestions. :-)

You're welcome. ;-)