# Drain Design error message ‘drains were affected by this operation’

<span dir="ltr" style="font-size: 14pt; font-family: Helvetica, sans-serif; color: rgb(0, 0, 0); font-weight: 400;">**Symptoms**:</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; color: rgb(0, 0, 0); font-weight: 300;">When designing a drain, you receive an error message:</span></span>

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/ggmoddk-etqogxy3bsejmre6en5njlhlwg-png.png)

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; color: rgb(0, 0, 0); font-weight: 400;">**Cause**:</span></span>

1. <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; color: rgb(0, 0, 0); font-weight: 300;">Elevation data was collected from low to high elevation where another drain connects.</span></span>
2. <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; color: rgb(0, 0, 0); font-weight: 300;">Drain was split with the Split Drain tool.</span></span>

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/elsccikbklziq8sutie8cmhecdxc2nkt7a-png.png)

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; color: rgb(0, 0, 0); font-weight: 400;">**Solutions**:</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; color: rgb(0, 0, 0); font-weight: 300;">Swap AB before designing so the drain is designed from high to low elevation.</span></span>

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/d5yrcunw4ibjdvitc0c2uwqfykmzpob17q-png.png)