High supply of the house will slow down the sellers market?

[Komron Levine]

what happens when there is high supply in the market? The prices will go down correct? I am asking this question coz there is a big project going in the same neighborhood where i want to buy a house, it is expected to have over 500 town houses and over 300 apartments along with shopping malls and many more. 

And my future house is just 12 mins away from this new project. Assuming if I get the house the future developments happening nearby will  effect the value of the house positively or negatively ?