The article found at the link below describes the hard time Western pecan growers are having getting enough good-quality irrigation water this year. This emphasizes the importance of managing the water we have here in the Southeast wisely.
You should be at 45-50% of your irrigation system’s full capacity in July for nut sizing. If you irrigate at full capacity now you will get the nuts too large and make them difficult to fill. If you have less than 20% of terminals bearing nuts you still need to be irrigating at the 45% rate now but you will only need to go to about 75-80% full capacity once kernel filling arrives (August) as opposed to 100% in August for trees bearing a commercial crop.