Geist Reservoir has an aquatic vegetation problem. Weeds and mud clog our shorelines, marinas, and boating channels. Over time, the Reservoir’s asthetic appeal and watersport recreation opportunities will become increasingly limited.
We have a vegetation problem because our Reservoir is full of nutrients. Most of these nutrients come from the mud (called sediment) at the bottom of the Reservoir. Mud comes from soil erosion.
Soil erosion is the result of a complex calculation involving rain patterns, soil conditions, geography, and land management practices. The only variable we control in this equation is land management. In other words, we cannot improve our Reservoir until we improve our land. Here’s why:
When it rains in Central Indiana, it pours. And when it pours on our mostly clay soils, water pools on the surface and then overflows into our storm drains, retention ponds, rivers, streams, and Reservoir. Heavy rains can overwhelm our drainage systems. When this happens we get soil erosion. Erosion deposits dirt into our water systems where it becomes food for aquatic plants. Incidently, this is why we have mud in “Mud Creek”.
Up until a few years ago, Geist Reservoir had an algae problem. This happened because 1) algae is very good at consuming nutrients and 2) nothing in the Reservoir is very good at consuming algae. Algae blooms limited sunlight from entering the water which in turn restricted aquatic plant growth. Then invasive zebra mussels happened.
Zebra mussels are so good at eating algae that since their introduction to Geist Reservoir a few years ago, we no longer have algae blooms. Except for days following heavy rains (soil erosion), water is extremely clear.
Aquatic plants, like algae, need light and nutrients to survive. Thanks to the zebras, light now penetrates down to the nutrient rich mud at the bottom our Reservoir. The algae population is kept in check by zebra mussels. And the aquatic plants are finally getting their day in the sun.
We humans also like a day in the sun. To make this possible, we spray the Reservoir with aquatic herbicides. This is a fairly cheap way to keep the Reservoir usable for a season. It is not a great long term solution.
Dredging might be part of a long term solution. But without changes to our land management practices, erosion will fill in the dredged areas after a few heavy rain storms.
So, here is how we can fix our Reservoir:
Step 1: Vote
Soil erosion rates are the result of zoning laws that dictate land management practices. We can expect no significant change soil erosion rates until our elected officials upgrade zoning laws and enforce better land management practices. Do you think it is possible to grow our economy and have environmentally responsible zoning that protects our Reservoir? Please keep this in mind next time you vote.
Step 2: Plant more plants
Central Indiana soil is mostly clay. Plants break up clay. Plant roots make channels in soil and improve water infiltration. Herbacious plant parts decompose and transform clay into hummus. Over time, plants make clay porous and fertile. Rainwater absorption rates improve. Less runoff means less soil erosion. Less soil erosion means less food for aquatic plants in our Reservoir.
The best plants to plant are the ones with really deep roots. Trees and shrubs are great. So are ornamental grasses and perennial flowers. But the biggest opportunity for improvement is with your lawn.
Typical Indiana lawns use grass species that have very short roots. Short root lawns do hold much water and do not break up clay soil. To look good, they require lots of fertilizer, irrigation, and weekly mowning. And after the first 1/4” of rain, they don’t absorb much water.
If you want to help our Reservoir and save a bit of money on lawn care, over-seed your lawn with drought tolerant grass seed. Drought tolerant seeds are newer cultivars of rye and fescue that have a nice thin blade like bluegrass but put down a very deep root. They require significantly less water and fertilizer to stay green. And as your lawn matures, deep roots will break up your clay soil which in turn will reduce runoff and slow soil erosion.
Drought tolerant seed blends are available everywhere from Costco and Home Depot to garden centers and specialty shops like Advanced Turf Solutions in Noblesville. Some of the more popular brands are Pennington Smart Seed, Scotts tall fescue blends, and Perals Premium. Perals claims a 12” root, once a month mowing, and once a year fertilizer. You can get it at Costco.
The best time to over-seed a lawn is right now. You should do it.
Step 3: Get involved
It takes a village to fix a Reservoir. That’s where the Geist Lake Coalition comes in. The GLC works with the Department of Natural Resources and the City of Fishers to find ways to maximize the recreational and aesthetic value of our Reservoir.
The GLC needs forward thinking leaders in government, retail, utilities, real estate, watersport recreation, education and the landscape industry. They need farmers and homeowners and entrepreneurs. We need people that want to help develop meaningful corrective actions that are economically viable and have long term benefits.
Thank you for being part of the solution. The consequences of inaction are too high for our home values, our environment, and our economy.