Sharring experiences in urban infrastructure delivery.

Fountains–Preston at Main Street

By: Tom Davis Category: Sidewalk Art, Sidewalk Fountains

There are two stone “vessels” either side of Main Street on the north side of Preston (map). Both stone urns were designed, built and installed by Brad Goldberg, an award winning sculptor/artist who works with stone. Be sure to read the posts here about his two vessels at Congress and Main and the “Bayou” in the fountain on Preston between Fannin and San Jacinto. All pieces are part of the City of Houston’s Art Collection.DSC_0197.JPG

The vessels here are taller than those on Congress Street and have a water pool in the top where the water runs over the edge and down the ridges creating a shimmering, cascading sheet of water reflecting sun light or the embedded up-lights in the base of the pool below. The vessels are supported on a concrete drilled pier to provide the solid immobile base needed to maintain the perfectly level upper bowl.

Each vessel is composed of five pieces of stone that match perfectly and could be transported from the quarry and carving shop in Cold Spring, MN. The sections are bound together and to the foundation by three stainless steel rods. The rods are fabricated in sections and surround the water supply pipe that fits through the fourth hole drilled into each stone section. As each section of stone was lowered over the three rods and the pipe the next pieces of threaded rods and pipe were added and the next stone lowered into place by a hydraulic crane.

Main-Preston fntn man guitar dancing red head.jpgOnce the last stone piece was in place stainless steel nuts and over-size flat washers were used to secure the stones into one unit. The three nuts and washers were sealed as was the water supply pipe inside a recess carved in the top stone forming the pool that provides a quiet still reservoir to recieve the water pumped from the nearby vault under the sidewalk. The upper pool is about 4″ deep and great care was taken to assure the rim was level and a thin sheet of water would run over all sides evenly.

These fountains include a winding wall with a pool at the top where water is pumped in via equally spaced pipes to create an even, quiet sheet of water cascading down the ridged face of the precast concrete wall into a pool below lined with black  smooth stones.MainAtPrestonFountainCtHouse4.jpg

The water cascading down the wall joins the water from the sides of the tall vessel and runs into a cone shapped swirling funnel that is the gravity return to the wet well next to the service vault. The water is  pumped from the well, through a filter, treated and returned to the pool at the top of the vessel and the long pool at the top of the wall.

Things we faced when building these fountains were:

  • The top of the precast walls forms a weir that must be perfectly level. Standard precast concrete is not perfectly flat lines and when placed on a standard poured in place concrete foundation requries leveling of the very heavy concrete sections. This difficulty of the leveling was compounded by the wall being curved.
  • We added took care in placing the many small pipes feeding the small pool at the top of the curving wall as the pool needed to remain “quiet” and the water sheet flow evenly over the entire length. We were fortunate that the different head losses in the different length pipe runs did not cause different amounts of water to arrive at the small pool unevenly. To also minimize the potential for uneven flow a 12″ diameter pipe feed the small lines that feed into the pool. The large pipe acts as a reservoir dampening out pressure variations.PrestonFountain.jpg
  • The water return line was up-sized due to concern that in these larger fountains the return water flow would not be quick enough to refill the small wet well before the oversized supply line, then pools and collection trough filled and water flowed back into the wet well.
  • To compound the concern about water return rates the vault and wet well on the west fountain are at the other end of the block–creating more travel time but also creating additional volumes in the connection pipe lines.

Lessons Learned – 1.  Fountains, especially those with sidewalks on both sides are a litter magnet and require daily retrieval of trash that blows in.  2. Unloading the heavy stones was to be done by the construction contractor with the stones being delivered by the artist–separate contracts. The problem was that the construction contractor who was required to provide the crane was not told to provide the special lifting device peculair to large stone. Unfortunately the artist did not have one to loan so we had to buy it. Not a big expense but also not at your neighborhood Lowes or Home Depot. Fortunately we had a very experienced sculptors–Brad Goldberg–who asked about it before the truck was waiting in the street.

The fountains were built as part of the Cotswold Program by the Houston Downtown Management District and the City of Houston. Maintenance of the fountains is provided by the City of Houston’s Convention and Entertainment Department.


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