North Texas is composed of a variety of soil types.   It is important to know what type of soil you have to determine the rate at which water will infiltrate the soil.  For example, mostly sandy soil will absorb water at a much higher rate than a mostly clay based soil.  If your lawn is composed of mostly clay (which most are in this area) and you trying to water for a long period to "water deep" you are more than likely paying alot of money to refill the local creek.  This is because most sprinkler systems have a much higher precipitation or application rate than than the soils infiltration or absorption rate.  Therefore, if you have pop-up spray heads with clay soil and you are trying to water for more than 10-15 minutes per station or zone, the water will run off or pool in your favorite "soggy spot" in the yard.  In this case if your requirement is 15 minutes of watering, it would be more efficient to water twice for 7 or 8 minutes with an hour or so gap in between. 

  Have you ever tried to fill a flower pot too fast and the water started to float on top of the soil, but after a minute the water would absorb and you could then add more water.  This is the same principal.  Now imagine if the flower pot was tilted or sloped.  Instead of pooling, the water would run off.  With as stressed as water is in our area and with our area continuing to grow, we all need to do our part to try to conserve water.