Greetings. My suggestion is that first, you should have had your attorney include a geographic limitation into your agreement, even if settled through mediation a custody agreement must be properly drafted to protect the children.
Next, contact her in writing and let her know that you do not consent to her removing the children from the area and that you expect at least thrity (30) days notice of any planned moves on her behalf. Keep of copy of the correspondence.
Make sure that the children are enrolled in more than just school (such as sports, etc.) in this area. Coach games and set yourself up as the boyscouts leader, etc. Keep all your custodial dates and mark on a calendar each time you have your children.
Janet L. Fritts
Attorney at Law
4101 Lake Boone Trail, Suite 500
Raleigh, North Carolina 27607
The response posted above is based upon the limited factual information made available and is not intended as a full and complete response to the question. The only reliable manner to obtain complete and adequate legal advice is to consult with an attorney, fully explain your situation, and allow the attorney sufficient opportunity to research the applicable law and facts required to render an accurate opinion. The basic information provided above is intended as a public service but a full discussion with an attorney should be undertaken before taking any action.