It seems obvious, but bears repeating; while golf course water features can and do fill multiple roles successfully, their primary function should always be kept in the forefront while planning. This focus must be maintained since specific design and placement requirements must be satisfied for any feature to perform its role successfully and efficiently.
As new planned developments shift their focus away from golf courses as the unquestioned centerpiece, for an expanded offering of recreational opportunities, water features like reservoirs will be pressed into new functions. Fishing, canoes, kayaks, and even paddle boats could be incorporated into the design for current or future amenities. Riparian zones, wetlands, marshes, and other wildlife habitats could include carefully planned walkways, educational materials and other elements. These features can be used to promote the value of the development for local families and schools, while protecting sensitive ecosystems.
Even if it’s not on the development calendar this year, allowing for this kind of expansion in the future is a wise strategy. Consider the placement and size of your primary irrigation reservoir. Could it be augmented with walking or jogging trails? Is there an access point where future kayakers could approach the lake without damaging vulnerable areas? Could one or more of your smaller ponds be stocked with fish? Is it worth taking time to work with an educator to document the establishment of a riparian zone or the restoration of wetlands for future educational programs?
An irrigation pond can be stunningly beautiful and support a vibrant ecosystem for local wildlife, but its primary purpose is to provide water for irrigation. It may even serve as emergency backup storage, so you’ll need to start by maximizing storage capacity. Bigger is better in this case, which is helpful, because expansive, natural looking lakes are the most visually appealing. When function comes into play, keep in mind that nightly irrigation activities will naturally draw down water levels. Extreme drawdown, though, will create muddy margins, expose your liner to erosion and damage, and destroy important marginal ecosystems. A key concept here, is that while increasing the average depth raises the overall volume of stored water, it’s the surface area of your pond that determines drawdown. A deeper pond will store more water for emergencies, but a more expansive pond will get you through your daily needs. (Details on calculating drawdown are below.) Another important guideline is to plan for your lake to be three feet deeper than the amount you want usable, even in emergencies, since draining water lower than three feet will cause whirlpools around the intake.
Of course, digging and building a bottomless irrigation reservoir to rival Crater Lake isn’t realistic or necessary. In fact, the ideal depth for most lakes is 15 feet, with 10 feet as the minimum. Deeper lakes may experience problems with aeration, which can lead to significant problems with water quality, appearance, and smells. These issues can eventually kill fish as well. If space limitations and water storage demand an exceptionally deep lake, you may need to add pumps and aeration to maintain oxygen levels, keep the water moving, and avoid dead zones.
The primary function of your pond should determine its location. Especially for irrigation ponds, it makes sense to place it in a central area at the lowest elevation. This helps to capture as much rainfall and irrigation drainage as possible. On relatively level sites, this also provides the best hydraulic conditions, which correlate to lower power requirements and therefore less expensive pumps. On sites with significant elevation changes, it may be more cost effective to establish multiple irrigation ponds for daily use with one central emergency reservoir. Otherwise, the equipment and energy required to regularly pump significant volumes of water uphill can be prohibitive.
Before you start digging, you’ll need to calculate your daily watering needs, evaporation, and replenishment rates, as well as the surface acreage of your lake. You can calculate the drawdown for irrigation purposes by multiplying the surface acreage in square feet by 7.48. That’s an equivalent of 1 foot of drawdown across your lake in gallons. If you know your irrigation rates, you can divide that number by the drawdown volume. Multiply the result by 12 and you’ll have the total drawdown in inches.
After allowing for evaporation and replenishment rate, it’s recommended to aim for a drawdown of no more than 6 vertical inches each night. If your calculations indicate the lake isn’t big enough or has an inadequate replenishing rate for your needs, it’s time to head back to the drawing board. More acreage, or even a second irrigation pond, are two options. Reducing irrigation activities, as part of an integrated movement toward sustainability is another.
Since you’re unlikely to be drawing water from other (smaller) ponds around your course, evaporation and replenishment are your main concerns for those. It’s best to contact your local county extension agency to help you calculate an average seasonal evaporation rate, since that will vary according to temperature, humidity, and cloud cover. Replenishment can come from irrigation runoff from surrounding areas, natural springs, precipitation, or even periodic topping off from your main irrigation lake. This is where liners become critical. Evaporation can be somewhat minimized, using plants and shade in the case of naturalized ponds located along the borders of your course. Yet, in small, fully exposed, fairway ponds, seepage should be eliminated.
Any water feature needs to avoid loss of water through seepage and leakage. Depending on the structure and location, uncontrolled seepage can undermine the stability of structures like a retention dam or, in extreme circumstances, even the fairway on the 7th hole. No one wants to see a sinkhole appear where there used to be a cart path. To avoid water loss, reinforced geomembranes like BTL’s AquaArmor are ideal for meeting the requirements for a durable, dependable liner.
In top golf courses around the world, water hazards can be incorporated into the design using almost any natural feature and may include some amazing, constructed ones. Lake Coeur d’Alene, for example, is a 32,000-acre natural lake, which features the world’s first floating green: the 14th hole on The Resort Course. Pebble Beach’s 8th hole has an unforgettable hazard - you may not make the carry, but you’ll never forget that time you lost your ball in the Pacific Ocean.
Hazards can be almost anything, and ponds are easy to build and are very widely used. However, if you have the room and the inclination to stand out, consider a bucolic creek or stream flowing adjacent to the fairway and cutting across it unexpectedly. (A diagonal cross will offer more options for the less skilled player.) The sound of gently flowing water, chirping insects and croaking frogs can add an unforgettable ambience. Of course, construction of an artificial stream requires a pump to move the water up so it can babble its way down again. A good, quiet pump, and even some solar panels, may be just the thing you need. Don’t forget, in a closed system like an artificial stream, water loss must be avoided. So, use of an impermeable liner is the way to go. Even in shallow streams, a layer of sand or small, rounded, river rocks, along with a few larger specimens to add interest, will both disguise the liner and present a charming look.
Erosion is a natural process that has created many natural masterpieces like the Grand Canyon, but it has become a genuine nuisance as civilization has placed its stamp on the earth. As urbanization spreads across the landscape, waterways are diverted, wetlands are destroyed, and the ground is sealed with pavement. All of this means that rainfall has nowhere to go. An inch or two of rainfall might not seem like much of a problem, but in this environment, it adds up fast.
Consider that the average golf course is about 150 acres and one inch of rainfall equals 4.7 gallons of water per square yard. There are 4840 square yards in an acre, so in a 24-hour period where 2 inches of rain falls (a mild event), an average golf course will need to take in nearly 7 million gallons of water; not counting any that flows in from surrounding developments.
All that water needs to go somewhere. Ideally, it will head toward your irrigation pond and backup storage reservoirs. If the rain is slow and mild, throughout a 24 hours period, the water has time to be absorbed and will flow gently to its intended destination. When the rainfall is concentrated in a shorter period, however, the volume, speed and force of the moving water can gouge out channels, carry away sections of bank, and flood sensitive areas. The damage can be both extensive and expensive to repair.
Intentional moving water, like creeks, streams, and brooks, bring in additional levels of complexity to a golf course; both in design and management. Natural streams and rivers travel along the path of least resistance, generally following natural hollows in the landscape and pooling if a ready outlet isn’t available. Over time, especially when storm runoff joins the equation, the water wears a path, eroding the soil and gradually digging a deeper, straighter channel. Deeper and straighter also means faster, which leads to bank instability and more extensive erosion.
Even with focused efforts on reducing the impact of storm events, both natural and constructed waterways are vulnerable to smaller effects. These include animals who approach the edges, mowers who venture too close on a turn, and struggling golfers who absolutely will play it as it lays. Direct damage to stream margins and vegetation also contribute to erosion problems and muddy, crumbling banks.
Your decision on how to handle bank erosion depends on a few factors. If your course is still managed with plenty of pesticides, herbicides, and fertilizers, you’ll need to first establish a vegetation buffer in the riparian zone, between the fairway and the water feature, to prevent an abundance of chemicals from dumping into your stream. This chemical combination can kill plants and fish, harm other wildlife, and trigger algae blooms in downstream ponds. None of these outcomes will reflect well on course management. Unfortunately, the need for a wide vegetation buffer might effectively prevent you from establishing a babbling brook or peaceful stream unless it’s located along the far boundaries of the rough. This placement, with longer grasses in the buffer zone, can make recovery of even a slight duff difficult.
If your course has begun to transition to a less chemical-intensive regimen, then your primary concern shifts to mitigating damage to the bank. The first option, if your stream is manmade and powered by a pump, is to manage the flow of your stream. Faster streams lead to more erosion, which adds sediment to the closed system, and can damage your equipment or even alter the course of your carefully designed feature. You can start managing the flow by adjusting your pump’s volume to the minimum level that achieves the effect you want, whether it’s simply visual or if you need burbling and splashing sounds to mask the rush of nearby traffic. Heavy rain events, however, are another issue altogether. The addition of a durable geotextiles, to minimize erosion, could be a game saver here.
For a natural appearance and more effective response to heavy runoff, the addition of riffles and pools will help manage the flow of a waterway, while also offering several benefits to small aquatic ecosystems. Riffles are small, fast flowing sections of a stream (think of rapids on a river) that pass over sections of river rock and gravel. The visible ripples are signs that the pure energetic force of the water is being deflected and dissipated by turbulence among the rocks. This turbulence also adds oxygen, which helps maintain water quality and support downstream ecosystems. Pools are deeper, sheltered areas where the water is generally calm. They are sometimes found along edges of the larger streams, sheltered by a fallen log, or even right behind a large rock. If your stream is large, and deep enough to support fish, these pools will be a favorite spot to hide and cool off during hot summer days. Anglers love them too.
Riprap is the quick, dependable, go-to, for managing waterway erosion in urban areas and agricultural setups. Riprap are the large rocks that line ditches, dam spillways, and other places where it’s necessary to break up the flow and intensity of moving water. It’s effective and useful, but rarely attractive. In cases where this level of erosion control is necessary, rootrap is potentially a more effective and more attractive solution.
Live staking, is a low-cost option that stabilizes stream and pond banks and adds beauty at the same time. Live stakes are live branch cuttings from trees and shrubs that thrive in water. River birch, black willow, elderberry, and red-osier dogwood are all good options. Freshly cut branches are stripped of leaves and twigs, cut into sections at least 18” long, and then pushed ⅔ of the way into the moist, soft soil along the shoreline. The plant species used for live stakes readily put out new roots under these conditions and within a year or two will have become thriving shrubs and young trees. Their roots continue to spread and weave through the soil, forming a mat that holds the soil in tightly. Live staking is a simple, quick, and effective project (so long as you remember which side of the stake goes up).
Live stakes can be used effectively on their own to develop a stabilizing root mat, but they can also be used for anchoring in conjunction with erosion control geofabrics. In the first year after planting live stakes, don’t expect to see much, if any, growth above ground. The primary goal of the first growing season is to establish a good root system. In subsequent years, you should see foliage and relatively quick growth.
Wattles and fascines both refer to small cylindrical bundles of living branches. Placed lengthwise in shallow trenches along the banks in a riparian zone, the branches immediately provide a physical barrier to erosion and double as a sediment trap. After a single growing season, the branches will have rooted and developed shoots along the length of the bundle, stabilizing the bank and essentially creating a protective shoreline fence. Wattles can also be anchored by live stakes. This approach is an inexpensive, effective way to quickly establish a full, attractive buffer with a variety of species. Live wattles or fascines can be purchased from nurserymen. Check out dormant plant or erosion control sections to find species like pussy willows, elderberry, arrowwood, and buttonbush.
Other tools can also be called upon to protect and restore degraded streams. Rootwads come from felled trees. When they are placed correctly, they collect sediment and help re-establish and stabilize banks. They’re also inexpensive and are great spawning points for fish.
When native plant species are enlisted to manage erosion in streams, rivers, lakes and ponds, the benefits are multiplied. Not only are trees, shrubs, and grasses much more interesting and attractive than piles of riprap, they also provide food, shelter and habitat for many varieties of wildlife, from turtles and dragonflies to. These modest strips of vegetation improve the quality and clarity of the water and provide hiding places for tiny fry who may grow to be next year’s whopper.
Riparian zones are the strips of land that run alongside streams or surround bodies of water. Since the water table is generally high and the soil is fertile in this zone, a dense variety of plants can typically grow here. Ideally, riparian zones exist even along water features in a golf course. This can be used to your advantage in the battle against erosion, because the deep and dense roots of riparian grasses, shrubs and trees are naturally suited to reinforce banks, soak up excess rainfall, prevent erosion, and improve water quality.
- In a cross-section of a riparian zone, the toe zone is located below the surface of the water, at its normal summer depth. This is a challenging area to establish plantings, especially where currents are high, but if the water is slow moving or still, cattails and bulrushes can establish quite well. Practically speaking, the toe is the weakest link of a bank. When rainwater erodes a toe sufficiently, the soil on the bank above it becomes unstable and the bank may collapse.
- The bank zone is inundated only once every year or two, when spring flooding arrives, and the channels rise to full. This zone is ideal for rhizome-spreading grasses like sedges and sawgrass. This zone might also be home to small bushy willows with multiple flexible stems and low-lying shrubs.
- The overbank zone is generally flat and may be flooded every few years, so the plants should be able to handle both occasional flooding and relatively drier years. This is a zone suited to shrub-like willows, dogwoods, alder, and birch in particular. If you’re planting here, avoid plants that have large inflexible stems since they can be damaged by the fast flow of periodic floods.
- The transition zone is further removed from the body of water and may be flooded only once in 50 years or so, so species that are suited to this area won’t be dependent on constant moisture. This is where you’ll find most of the larger trees.
- The upland zone is entirely above the floodplain. Contrasting with the previous examples, the primary requirement here is for drought-tolerant species.
Erosion control should be focused on the bank zone, with some support in the toe and overbank zones. Moisture loving grasses that spread by rhizomes (rootstalks) in the bank zone, and may even tolerate the toe zone, are excellent choices. Often called stabilizer plants, they have substantial roots which can interlace and create a reinforcing mesh that runs throughout the bank. Species of plants like cattails, bulrushes, reeds, sedges, switchgrass, sweetgrass, dogwoods, willows and alders all contribute to highly stable banks once they’re established. When planting in your riparian zones, try to select native species that are already well suited to local conditions and may even offer unique support to native insects and other wildlife. Your county agricultural extension agent can advise you on which species are beneficial for your area.