Estancia Ditch Improvements

Typical of other areas of Santa Venetia, the northeastern portion of the community (near the Open Space Preserve) was developed on a tidal marsh that was filled in with soil in the 1950s. Immediately following construction, stormwater runoff drained via gravity to the adjacent pasture land. In 1985, the pasture was restored to the marsh you see today.

Over time, the weight of the homes, roadways, and imported soil fill compressed the underlying soils and the land sank. The land sank so much that it wasn’t long before it was below sea level, requiring the construction of levees to protect the community from tidewaters. Following the levee’s construction, Pump Station No. 5 was constructed to pump the water over the levee and into the creek and Estancia Ditch was dug along the base of the levee to drain the water from the neighborhood.

Although the Estancia Ditch and Pump Station No. 5 system provide some relief from flooding, local properties that drain to the ditch still experience flooding problems.

• The ditch’s flat slope, along with its narrow width and relatively shallow depth, makes it difficult for water to flow to the pump station during larger storm events and encourages ponding, vegetation growth, and water stagnation in the summer months.
• The stormwater drain pipe and drainage inlets for Estancia Way are too small to carry larger storm flows to the ditch. This system, which was originally designed to flow into the adjacent pasture/marsh, now terminates at the ditch a foot below the ditch bottom, further limiting its ability to drain.
• To provide additional protection from flooding the District currently stations a portable pump at the end of Estancia Way and operates it during large storm events to pump water from the ditch, over the levee into the marsh. Ditch improvements would eliminate the need for this pump and provide more reliable flood protection..

Several alternatives have been considered, including installation of an additional pump station, construction of a concrete lined channel, and reconfiguring and relining of the current ditch. The preferred alternative would involve the following:

• A steeper, wider, and deeper ditch would be constructed in the same location as the existing ditch, tripling its current capacity and providing ample stormwater drainage for a large (i.e., 100 year) storm event. The current need for the portable pump at the end of Estancia Way would be eliminated.
• The ditch would be lined with environmentally-friendly interlocking concrete blocks that would not only drain water faster, but also provide for quicker and more affordable maintenance. Ponding, vegetation growth, and water stagnation that are prevalent in the present ditch would be reduced.
• The storm drain system on Estancia Way would be replaced with larger pipes and inlets to increase the amount of water it can carry to the ditch. Water carried by the new storm drain system would reach the ditch above the ditch bottom, enhancing its ability to drain.
• The inlet to Pump Station No. 5 would be lowered and widened to account for the new size and slope of the ditch.

The construction of an additional stormwater pump station is not necessary to meet the drainage needs of the area and would be more expensive than the preferred alternative solution. An improved Estancia Ditch (as proposed) would have the capacity required to effectively drain water to the existing Pump Station No. 5 during large storm events. Moreover, Pump Station No. 5 is already sized to handle the water it would receive from the ditch and can pump it over the levee. Finally, regular maintenance of a new pump station would place further demand on an already strained budget.