Combine broth and water in a large saucepan. Place over medium heat and bring to a boil. Reduce heat and simmer while preparing the risotto.
Place butter in a large skillet. Melt butter over medium high heat.
When butter is melted, but not burnt, add onion, carrot and asparagus stems. Cook, stirring constantly, 1 to 2 minutes or until the onions and carrots are tender.
Stir in garlic and white wine, Cook, stirring constantly, 1 more minute until the wine boils.
Add rice and 1 cup simmering liquid. Cook, stirring frequently, until the liquid is absorbed into the rice.
Continue to add simmering liquid, 1 cup at a time, cooking until the liquid is absorbed, stirring frequently.
When 4 cups of liquid has been absorbed, stir in asparagus tips.
Test rice for doneness, and continue adding 1/2 cup of liquid at a time until the rice is tender but still firm and creamy.
Stir in Parmesan cheese, allowing the cheese to melt into the rice.
Remove from heat and serve hot.