Heat the water over medium heat in a large stock pot.
Cut the potatoes into 1 inch pieces and add to pot.
Slice the celery into 1/2 inch pieces and add to pot.
Slice the carrot into 1/2 inch slices, quarter them, and add to pot.
Let all the vegetables cook for approximately 30 minutes. The potatoes will soften and thicken the water.
While the vegetables cook, prepare the chicken: Brown the breasts on each side in a skillet. Remove from the pan, let cool slightly, and then dice. Return to pan to cook completely, approximately 5 more minutes.
When the carrots are just soft enough to pierce, season the stew. Add the chicken to the pot, and then the dumplings, as noted below.
For the dumplings: Combine the flour, baking powder and salt. Cut in the shortening, and then stir in the milk until just combined.
Drop the dough by heaping spoonfuls into the stew. Simmer for 10 minutes, then cover the pan and steam for 5 - 10 minutes. Serve immediately.
Other veggies that work well are mushrooms, peas, diced green beans, lima beans, etc. Whatever you might like!