Key Points
On sites without freely-draining sandy soil, at least some storm drainage will likely be needed to ensure the health of the turf and firm playing conditions.
Storm drainage (both overland and subsurface) is designed by the golf course architect and a Civil Engineer with due consideration to the project budget and local regulations concerning the volume and quality of stormwater that is permitted to be released off-site (if any).
Sustainable Drainage Systems (SuDS) should be incorporated with subsurface drainage to take advantage of numerous environmental benefits.
With the completion of site preparation and clearing, two separate operations begin in earnest and simultaneously – bulk earthwork and the installation of storm drainage. To learn more about bulk earthwork, see Step 7: Bulk Earthwork.
This article will take a closer look at the circumstances for which subsurface storm drainage is needed and why good drainage is so important for the health of the turf and the playability of the golf course. We’ll also explain what Sustainable Drainage Systems (SuDS) are and how to use SuDS features to ensure that the storm drainage system isn’t contributing to unnecessary downstream flooding, erosion, or pollution.
From Sandy Links Land to Heavy Clay Inland
The sandy links land where golf originated is often characterized by a very deep profile of free draining sand so, no matter how intensely it rains or how much land area is draining onto the golf course, the storm water is normally able to infiltrate into the ground essentially immediately. In practical terms, this means that very little, or no, drainage is necessary to move “nuisance water” off a sand-based golf course after a storm to maintain firm ground conditions in any weather. Thus, the suitability and economy of sandy, free-draining soil to golf is obvious:
In the face of oversaturated golf markets, upwardly spiraling construction and maintenance costs, and tough environmental restrictions, one of the best ways to give a project a leg up is through site selection. Sandy courses offer conditions that are almost impossible to replicate on other types of terrain, and they are more economical to build and cheaper to maintain. They provide great golf in spite of tight budgets, water restrictions, and many other issues confronting the golf industry today. (Waters, pg. 6)
It’s only when golf courses began to be constructed further inland that heavier, less free-draining soil types (silt and clay) were encountered, necessitating surface and subsurface drainage systems to keep the golf course from perpetual sogginess. Wherever the percolation rate of the soil (as typically determined by the consulting agronomist through soil testing) is less than the volume of water trying to drain into that soil (which is found by multiplying the typical storm intensity by the size of the catchment area), then you begin to have problems with soggy ground and unhealthy turf characterized by shallow or anaerobic root systems.
The land on which a golf course is built may have many different soil types with many different infiltration rates so it’s always a good idea to conduct a thorough site investigation (including soil tests and observation of how long an area remains wet after a storm event) before committing to the cost of buying and installing a lot of subsurface drainage pipe.
Subsurface Drainage System Design
Once it has been determined that some storm drainage will be needed, the golf course architect will need to balance the cost of a “perfectly” drained golf course versus the reality of the project budget. Higher budget projects are able to overcome poorly draining soils found on site by, for example, capping the entire golf course with a uniform layer of free-draining sand, in addition to installing an extensive network of underground drainage pipe. Lower budget projects will require more creative solutions, such as creating slopes and swales with enough pitch to move water overland off the playing surface and into out-of-play areas as quickly as possible. Costly subsurface pipe can then be reserved for the most problematic, low-lying, and habitually wet areas of the site, in addition to maintenance-intense golf features, such as greens and bunkers.
During the design phase, the golf course architect will often use his or her proposed grading plan to help lay out the storm drainage system schematically to better estimate how much subsurface drainage is necessary versus the drainage that can be achieved overland and without subsurface pipe. As a general rule of thumb, water will travel overland over maintained turfgrass when the grade is 3% or steeper but that water should be routed to an out-of-play area, or collected into a catch basin or drainage sump, after no more than 150 feet (50-meters) of overland flow. An example of a schematic subsurface drainage plan is below:
Once the schematic subsurface drainage network has been laid out, the golf course architect can engage with a Civil Engineer to finalize the subsurface drainage design. The Civil Engineer will determine the appropriate pipe sizes and calculate the inverts of the catch basins, pipes, and outlets based on:
1) the size of the drainage catchments,
2) the infiltration rate of the soil, and
3) the typical and historical rainfall data.
A fourth consideration that is increasingly relevant is the impact of climate change and how to prepare for the extreme weather events that are now happening with greater frequency. Climate change is difficult to accurately quantify but, at the very least, due consideration should be given to the vulnerability of key infrastructure when laying out the storm drainage system.
A chart prepared by a Civil Engineer showing proposed pipe sizes, inverts, and slopes for a subsurface drainage system design is shown below. This information, when finalized, will ultimately be transferred to the drainage plan to be bid upon by the golf course builder or drainage sub-contractor:
Sustainable Drainage Systems (SuDS)
Once storm water has been moved off of and away from play areas, it is important to consider where and how this volume of water is going to be stored or where and at what rate it can be discharged offsite. Many golf courses are able to collect and use storm water to recharge amenity and irrigation storage lakes. However, if not all storm water can be stored on site, most developed countries now regulate the holding time and treatment of storm water before it can be released off-site, in an effort to control downstream flooding, erosion, and pollution.
Typical subsurface drainage systems are designed to collect and move surface water as quickly as possible - without consideration for pollutants and contaminants. That is why a secondary drainage system that moves the water slowly overland, also known as a Sustainable Drainage System (SuDS), should ideally be designed in combination with the subsurface system.
The key feature of a SuDS is that it slows the flow of runoff water to reduce the quantity, and increase the quality, of the storm water that has been collected. By slowing the water down, more surface water is able to percolate into the ground, where it will be naturally filtered and returned to groundwater. Examples of SuDS conveyance methods include small streams and broad, shallow channels that are full of native plant life, which will naturally slow down the flow of the surface water and remove pollutants by bio-filtration.
These conveyance features can then discharge the storm water to natural or constructed wetlands and marshes, which hold storm water temporarily and allow additional particulate pollutants to settle out. All of the typical SuDS features have the added benefits of increasing the site’s storage capacity and also of serving as natural amenities by attracting a wide variety of wildlife to enhance the biodiversity of the site. Other types of SuDS features that can be incorporated into the design of the overall development include green roofs on buildings, permeable pavement for parking areas and cart paths, and rain gardens in landscaped areas. Any feature that slows the flow of runoff water and allows for ground infiltration is beneficial.
A summary of the advantages of incorporating a SuDS into the drainage design:
Reduces flood risk downstream by lowering the peak flow volume;
Increases the site’s water storage capacity, which can help to alleviate some of the extreme storms and droughts that are now happening in greater frequency due to climate change;
Improves the water quality of the storm runoff through bio-filtration;
Allows water to percolate into the ground, naturally removing pollutants and recharging groundwater;
Significantly less costly than subsurface drainage pipe;
Attracts wildlife to enhance biodiversity;
Can be utilized as an attractive aesthetic and/or strategic element on the golf course.
Practical Considerations
A SuDS system will need to be maintained over the long-term. The water features will have to be accessible so the native vegetation can be managed, built-up sediment can be removed, and flow paths can remain unobstructed. A buffer zone should also be maintained around the SuDS features to prevent large storm events from overwhelming the features and also to help attenuate run-off containing chemicals from intensively managed areas of the golf course. A hydrologist or geomorphologist can review existing site conditions, determine required storage capacity, and offer technical assistance in the planning and maintenance of the site’s SuDS features.
Drainage System Installation
As parts of the site become more accessible (thanks to clearing and bulk earthwork operations), the installation of the subsurface drainage system and SuDS can proceed. The drainage sub-contractor will have surveyors or grade checkers mark the locations and inverts of each subsurface drainage feature so they can be installed to match the Civil Engineer’s design to a high degree of precision.
The largest and deepest pipes are installed first, followed by progressively smaller pipes as low points, bunkers, tees, and greens are graded to design subgrade levels. The final step is to ensure that all pipe trenches have been backfilled and compacted properly to prevent future settling. Any damage to finish shaping that has occurred during the installation of the drainage system will need to be repaired to the satisfaction of the golf course architect.
SuDs features will be created as shaping and landscaping operations continue with the assistance of a hydrologist or geomorphologist.
Contact Sustain Golf for more information!
The European Institute of Golf Course Architects (EIGCA), in partnership with the GEO Foundation, has developed a continuing professional development program for its members called Raising the Standard of Sustainable Golf Course Development, or RSSGCD. This is the industry’s only structured program in the world to specifically train golf course architects in sustainable golf course design, construction, and maintenance best practices. A Sustain Golf team member has attained Stage 3 of this rigorous program.
A Sustain Golf team member is also currently serving on the EIGCA’s Sustainability Committee and is a GEO Certified Accredited Sustainability Verifier.
We firmly believe that common sense sustainable design, construction, and maintenance practices are the keys to the long-term survival of the game of golf. We aspire to be on the leading edge of applying sustainability concepts to golf course design, construction, and maintenance.
We will spend every day for the duration of the project on-site and/or coordinating with all contractors, subcontractors and professional consultants to be sure that no opportunities are lost and that the best golf course for your property is realized.
We would be happy to make recommendations or answer any questions that you might have about typical design documentation or the tender process. Visit www.SustainGolf.com or contact us at the following address for more information: Contact@SustainGolf.com.
Up Next:
Step 9: From Rough Shaping to Fine Shaping
Sustain Golf is a collaborative group of like-minded qualified golf course architects. We are also qualified and experienced as civil engineers, vertical architects, and project managers. We have the breadth and diversity of experience and knowledge to offer a full suite of golf course design and construction services, from first concept to opening day on your new or remodeled golf course.
References:
Hurdzan, Dr. Michael J. Golf Course Architecture: Design, Construction & Restoration. Chelsea, MI: Sleeping Bear Press, 1996.
Waters, George Sand and Golf: How Terrain Shapes the Game. GOFF BOOKS, 2013
Susdrain Website. Retrieved from https://www.susdrain.org/delivering-suds/using-suds/background/sustainable-drainage.html
Photo Credits:
Retrieved from https://en.wikipedia.org/wiki/Drainage
Peer Review:
Dr. Keith Duff, former UK government wildlife agency Chief Scientist, current Golf Environment Consultant
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