Ongoing concerns about Mission Bay have not been limited to what goes on at the surface. In response to complaints that Mission Bay is often too shallow to rent boats to tourists and other visitors, the Mission Bay Park Committee (MBPC) recently asked the city to review the bathymetry — or underwater topography — and possible need for dredging. Citing a quote from a similar report on the Mississippi Delta, Keith Merkel of Merkel & Associates, Inc., said, “We don’t have a sediment problem. We have a sediment distribution problem.” Though many mark 1961 as the beginning of the transformation from False Bay to Mission Bay, it actually started with the diversion of the San Diego River into the bay from 1852 to 1929. Initial dredging also began then. Bahia Point was then created. The dredging of West Bay, a channel to De Anza Cove, Quivira Basin and a main channel to Mariner’s Basin followed. Construction for the expansive manmade bay was completed in 1961. Since then, Tecolote Creek, the Mission Bay channel and Fisherman’s Channel have been dredged and Sail Bay expanded. Further maintenance includes the removal of a shoal at East Ski Island, the reconfiguration of West Ski Island and various shoreline stabilization projects. The result, Merkel said, is an environment where sand moves but with minimal fluctuation. Tidal and wave action account for most of the sediment movement, he said. Sand enters the bay through an entrance channel at the intersection of Pacific Beach and the San Diego River as well as Rose and Tecolote creeks. Wind, waves and oceanic swell erosion also move sand into the bay. Urban storm drains and particles in the atmosphere put a less significant amount of sediment into the system. Sand leaves the bay when tides push it through the entrance channel. Dredging as well as shoal and beach maintenance also remove sediment. Mission Bay is also home to 856 acres of eelgrass. The plant serves as a fish habitat and provides shoreline stability and microbacterial benefits, Merkel said. “It’s a pretty big deal,” he said. Asked how eelgrass can be preserved, Paul Jacob of the city’s Park and Recreation Department said the plant cannot be avoided in the dredging process. The question, he said, is how to mitigate any damage. Due to coastal regulations, for every acre of eelgrass destroyed, 1.2 acres must be planted, he said. The city has no immediate plans to dredge, Merkel said, and has not determined a timeline for any future projects. Noting that there is some shoaling in areas, Merkel said that most of Mission Bay shows little evidence of sediment deposits. Over the past 10 years, the bay has gained 483,880 cubic yards. While that sounds like a lot, Merkel said it amounts to an average accumulation of .16 of an inch over 2,299 acres. The sediment accumulation is not dangerous, according to Merkel. The majority of the bay, he said, is in the 12- to 6-foot range. “That’s pretty much what you expect,” he said. The Mission Bay Master Plan, a blueprint for park development, currently does not identify dredging as a capital improvement project. The committee has long been concerned with how it will fund wetlands restoration, improved bike trails and other improvements outlined in the master plan. To that end, the committee believes more of the roughly $50 million generated annually by SeaWorld, the park’s hotels and other lessees should go toward capital improvement projects. The Mission Bay Park Initiative, which would funnel the lion’s share of park revenues back to Mission Bay instead of the city’s general fund, will be on the November ballot. “It’s a very important issue,” MBPC chairperson Rick Bussell said. The committee plans to discuss the initiative at its Oct. 7 meeting. The location will be announced. In other MBPC items, Capt. Shelley Zimmerman of the San Diego Police Department told committee members that overall beach crime dramatically declined this summer. In addition to recent statistics from the Fourth of July and other busy beach holidays, the MBPC reviewed the results of a comprehensive bathymetry study at its Sept. 9 meeting at the Santa Clara Recreation Center, 1008 Santa Clara Place. “The summer was very family-friendly,” Zimmerman said. Though several million visitors hit San Diego’s beaches, “every day was a relaxed atmosphere,” she added. The Fourth of July, the holiday that has been at the center of the beach alcohol debate, saw a “huge reduction” in citations, Zimmerman said. According to the Northern Division captain, police made 10 felony arrests this year, compared to 23 in 2007. Misdemeanor arrests resulting in jail were down from 145 in 2007 to 56; misdemeanor arrests resulting in citations dropped from 799 to 404. In 2007, police sent 112 individuals who were drunk in public to detoxification centers. This year, 33 people wound up in detox. Traffic citations went from 600 to 234, parking citations from 1,669 to 326 and vehicle impounds from 98 to 40. Memorial Day and Labor Day showed similar trends, said Zimmerman. “These are remarkable numbers that give us a snapshot of how family-friendly the summer was,” she said. “This year was night and day.”