What is causing the brown patches in our sod?
The waterfront is beautiful but this is a difficult area to grow and maintain grass in this location. There may be several reasons for browning of the sod such as poor soils, poor drainage, close mowing, lack of moisture, heat from the bulkhead, etc. Also, Brown patch, a fungal disease is starting to show up in turf.
You did not mention the type of grass that was installed and how it was managed. If Turf type tall fescue, it can be susceptible to brown patch. This is a common summer disease of cool season turfgrasses and temperature and humidity favor this disease. Avoid spring applications of fertilizer. If you applied fertilizer, this can be a factor. Most turf recovers in the fall with a return to rainfall. http://extension.umd.edu/hgic/brown-patch-lawns
Also, There is a new fertilizer law that you should be aware of. It restricts application of fertilizer within 10-15 feet from waterways. This is to prevent excess nutrients from washing into the Bay. Here is more about it http://mda.maryland.gov/SiteAssets/Pages/fertilizer/HowToFertilizeYourLawn.pdf
You will always be battling the heat from the bulkhead, poor maintenance, poor soils, etc. At this point all you can do is take a low maintenance approach such as mowing/grass cycling to the proper height; http://extension.umd.edu/hgic/plants/mowinggrasscycling-lawns
and water during dry periods http://extension.umd.edu/hgic/plants/watering-lawns.
The lawn will thin out. In the future you may want to think about replacing with pavers and low growing groundcovers, pathways with gravel or coarse sand, etc. Reducing your lawn area is good for the Bay. See some lawn alternatives.
Also, as part of the low maintenance approach to the turf area, you can overseed or seed bare spots in early fall to thicken it up. mh