I have the park boundary for Point Reyes National Seashore (https://irma.nps.gov/DataStore/Reference/Profile/2224545?lnv=True) and the NHD data for that park boundary. I want to do a drainage density analysis, but I don't want to include the 400m of water that extends beyond the shoreline in my area, not to mention the bay. I want to clip the park boundary to the extent of the shoreline, but the shoreline is an incomplete polygon (the park is connected to land!) so I can't actually clip it.
What is the best method to clip this to the seashore in a relatively quick manner?