3 cups reduced-sodium chicken broth
2 cups water
3/4 pound asparagus, trimmed and cut into 1-inch pieces
1 small onion, finely chopped
4 tablespoons unsalted butter, divided
1 1/4 cups Arborio rice
1/4 cup dry white wine
3/4 pound medium shrimp, peeled and deveined
1 tablespoon grated lemon zest
1/4 cup grated parmesan
2 tablespoons chopped flat-leaf parsley