1. Бы - subjunctive mood
2. Стала - denotes action, doing something
3. Водоем - i would say it implies any artificial or natural lake, pond (usually you can see the borders, so a sea or large river would hardly fit)
4. провинциальные жители - those living further from central towns, sometimes village dwellers
5. продлёнка - elementary school slang (sometimes pupils in elementary school stay after normal classes at school, they do homework and some other stuff and go back home later, from продлевать - prolong, extend)
6. знакомствами - a bit awkward use of this noun, may refer to people or things.

imho, the text needs some minor stylistic corrections (as it's a personal blog-like text you can't be 100% sure the text is absolutely free from mistakes)