Altimetry enables to monitor sea level in the open ocean - around 3.3 mm/yr globally on average for the past 25 years. However, consequences are most sensitive on the coasts and islands. Miami (where the last Ocean Surface Topography Science Team meeting was held late October 2017) is one of the places where sea level rise can cause a number of damages. The city is very close to the sea, and at a very low altitude, so any above-normal sea level anomaly is threatening  part of the city of flooding. High tides, tropical storms and hurricanes, but also changes in the Florida current can cause such anomalies. The land can also be moving - up, or down, as can be measured, e.g. by Doris stations. 

Mitigation projects are ongoing by the Miami Dade County to try  and avoid the worst of the damages. Dikes, road elevation, mangrove development etc. are under construction or study.If altimetry can't measure at such local scale, the open ocean measurements are giving a trend and values for better estimates or forecasts near to the coasts. WIth SWOT, high resolution coastal measurements will be provided by the satellite, thus providing the sea level variations directly.