It’s easy to think of a constructed deer pond as essentially a bathtub full of water that will remain clear and pristine until it’s time to fill it up again. Unfortunately, that’s not the case, even if you are supplying all the water yourself without allowing any runoff to enter your pond. Every interaction with the environment, from deer stepping into the margins to small creatures taking a quick drink, to wind carrying dust and pollen that falls onto the surface, brings foreign matter into the pond. It’s your job to plan and manage your pond so that it continues to attract deer by offering plentiful, healthy water.
Before you give up on the idea of adding a hunting pond to your property, remember that natural waterways and surface waters can suffer from the same problems. So, we’ll talk about some of the common issues that can pop up and how they can be addressed.
An Excess of Algae
Everyone has heard about algae and what a nuisance they are, from algae blooms that produce deadly toxins to nuisance algae that forms smelly mats on the surface and shores of ponds and streams. The kinds of excess algae in these examples are, without a doubt, signs of a disturbed and unhealthy ecosystem, and should be addressed. Still, algae in their various forms actually fulfill important roles in a healthy aquatic ecosystem - one of the most important being providing food for species at the lower end of the food chain. If you were to address algae by following a “scorched earth” policy to eradicate it all, you would have a whole host of different problems, and algae would inevitably return to your pond anyway. The key to preventing algae problems in a pond is appropriate management of those factors which encourage excessive growth in the first place.
Algae thrive when nutrients, sunlight, and oxygen are plentiful. Warm temperatures speed up reproduction, which is why severe algae blooms typically occur in the late spring and summer. Shallow ponds, located in full sun, are ideal habitats for algae. When conditions like this strongly favor algae, they reproduce rapidly, outcompeting other aquatic plants and reducing oxygen levels until invertebrates and other pond life suffer and die. The problem here is that water with extremely low oxygen levels promotes the growth of anaerobic bacteria. When anaerobic bacteria dominate a pond, they produce hydrogen sulfides, producing that typical rotten egg smell. That smell, then, is the hallmark of severely stagnant water. Deer and other wildlife instinctively avoid such poor-quality water sources.
If you’re concerned about algae and its attendant problems, avoid opting for chemical solutions, which treat the symptoms while ignoring the source. Instead, identify likely causes and work on mitigating them. Choosing a shady location for your pond and opting for a deep rather than shallow profile are excellent strategies to minimize algae problems from the design stage.
Nutrient-Rich Runoff
Most algae are plants that photosynthesize, even at the microscopic level. They need nutrients in order to grow, the same way your houseplants and crops do, and if there’s an excess of available nutrients, fast-growing algae, just like weeds, will happily multiply and consume them.
Ideally, a well-established aquatic plant community will consume whatever nutrients are available so that algae never get a head start. Sometimes, though, too many nutrients find their way into ponds or streams and the whole system can be jolted out of balance. This is key—algae blooms cannot happen without an abundance of nutrients, so start your search here.
Probably the most common source of excess nutrients is surface runoff from fields where fertilizer is applied or where livestock gather and defecate. When irrigation or storm runoff flows across the soil, it picks up waste and nutrients, ultimately delivering the nutrients into a pond, a stream, a wetland, or the like. Check for fertilized fields, food plots, pastures, or livestock feed stations that are situated above your pond’s position in the drainage basin.
There are several techniques you can employ to deal with nutrient-rich runoff, but again, the most efficient solution is to tackle it at the source. Farmers can switch to low-pressure or soil-level irrigation systems or use berms and ditches to direct and capture irrigation runoff for re-use. This benefits everyone—farmers can save money on valuable water, you’ll have much higher water quality in your hunting pond, and the entire downstream ecosystem will be healthier.
Marginal Plantings
Sometimes it’s impossible to pinpoint a single source of troublesome runoff, or your neighboring farmers may not be on board for updating their irrigation practices. In that case, you can implement a few natural solutions that will protect your deer pond and might even make your deer happier. Pond margins are an ideal place for establishing a variety of fast-growing plants with strong root systems. Planted along the margins of a pond, they are not only first in line to absorb nutrients from incoming runoff, but they secure the soil and trap incoming sediment. This is a critical consideration once you start thinking about midges and other disease vectors that can decimate your deer population. Some marginal plants even double as a food source for deer.
It’s a good idea to consult with your county extension service or local DNR to find out what plants work best in your area for nutrient uptake and soil stabilization, with an eye to species that can withstand the feeding habits of deer. The perennial Sagittaria latifola (broadleaf arrowhead, katniss, or duck potato) is a popular choice for this purpose. Its native range stretches from southern Canada, across most of the US and Mexico and continuing down into South America. It thrives in wet areas such as on pond edges where it quickly absorbs available nutrients, producing tasty and nutritious tubers, shoots and seed heads that can be enjoyed by both humans and wildlife.
