Even though I cannot control the weather, it makes me feel blessed when we have rain and things green up and grow like crazy. (especially the lawn! lol) But have you ever wondered what effect rainwater has on a pond ecosystem? Here is what I found out! -By B. Chudek
Effects of Rainwater in a pond:
The biggest effect to your pond during a rain storm could be from water running off the lawn or gardens into your pond. The run-off picks up fertilizer, bits of leaves, and nutrients from soil and dumps it into the pond.
All the extra nutrients super-feed algae! We get calls for help with algae blooms a day or two after heavy rains. There is a pretty simple fix for ponds after a rainstorm.
DO: To prevent an algae bloom after a rainy day, add a squirt of extra bacteria * to your filter!
Is Rain good for ponds?
Fish like it when it rains. Little bugs get knocked into the water and the fish enjoy the extra snack!
When we get that “Once-in-100-years-rain-storm”, you may see some fish die due to water pH crashes and loss of oxygen. Extra leaves and debris blown into the pond take oxygen as they break down. Combine that with power outages and fish could be left gasping.
In eight years of pond ownership, we have only had fish die in our pond once from a summer thunderstorm and I think their death was caused by loss of oxygen from power outages and aeration more than pH or temperature changes.
DO: Check your pump and aeration after a storm to make sure they are running! Check your fish. If they are acting normal, don’t worry about the rain. If you notice the fish are gasping near the water’s surface, tilting, or otherwise acting unnatural, you could use a battery powered aerator similar to this*.
Does rain water aerate a pond?
Wind, waves, and heavy rain can all help aerate a pond but don’t count on a gentle spring rain to be a primary aeration source. Aeration is key to maintaining a healthy ecosystem because it adds dissolved oxygen into the water. Good bacteria need oxygen to live. Good bacteria break down nutrients and fish waste which is why a waterfall or aeration stones or bubbler help SO much! Regularly aerating is a safer bet than waiting for rain.
DO: Review your pond aeration. If your pond experiences these symptoms, consider adding aeration.
Check your pond for these symptoms:
-the pond is smelly
-you see thick muck on the bottom
-the fish are unhealthy or dying
-algae is a constant problem
-poor water clarity
-high pH, nitrogen, and phosphorus readings
Rainwater is good and does not hurt a pond ecosystem (unless its a flood!) There are other ways to use rain in and around a home, too. If you are interested in harvesting rainwater to use for irrigating your lawn, watering a garden, or even reusing in your grey water uses like washing machines, check out the link to Aquascape inc.’s rainwater harvesting system.
*This post contains affiliate links. Minnesota Waterscapes may receive reimbursement from purchases made through these links.