Allah, Most High says, {Say, 'See ye? If your stream was lost one morning (in the underground), who then can supply you with clear flowing water?} The Prophet (pbuh) said, "Do not withhold excess water to withhold pasturage.”1

"Whoever denies others his surplus water or pasturage, Allah shall deny him His blessings on the Day of Judgment.”2

"There are three people whom Allah will not speak to, look at, or exonerate on the Day of Judgment, and who will have a painful torment: he who withholds excess water from a traveler in the desert, he who sells merchandise after 'Asr (late afternoon) swearing by Allah that he paid more for it than he actually did, and a man who gives the pledge to a governor only for the sake of this world, and is only loyal if he gets something of this worldly life.”3

Al-Bukhari adds to the above hadith the following, "Whoever denies others his surplus water, Allah will say to him, "Today J will deny you my bounty as you did with what you could not create.” 4