Rainfall as a Resource
For millennia, people prayed for rain. It nourished crops, supplied drinking water for families, livestock, and wildlife, and even aided transportation along rivers and streams. But as humans shifted to dense urban living, rain turned into a problem we wanted gone, and gone fast. This change from a "hydrophilic" to a "hydrophobic" society happened gradually, driven mainly by urban density. As cities grew, we replaced permeable, crop-covered land with impervious pavement, roofs, and concrete. Our modern buildings and infrastructure also tolerate flooding poorly, so we've engineered ourselves to resist runoff at all costs. Yet rainfall remains essential. The life-sustaining regeneration we once valued it for is still vital, urbanization just made it inconvenient. Traditionally, the fix has been bigger, faster drainage systems that rush stormwater straight into the Gulf of America. Efficient, yes. Sustainable, not really.
These engineered conveyances leave little habitat for fish, birds, or native species. They force us to seek water elsewhere for ourselves and for our animals, while we either switch to drought-tolerant landscaping or rely on irrigation often sourced from treated drinking water or groundwater. We do capture some rainwater productively. Large reservoirs like Lake Conroe, Houston, and Livingston store it for supply. These valuable long-term sources however have their drawbacks: construction displaces people and wildlife, sedimentation reduces capacity over time, dams need constant monitoring and maintenance, and losses to evaporation and infiltration are significant. In the Greater Houston area, subdivision design standards now favor detention ponds. Many are built as "wet" facilities that hold water as amenities. Residents love the views and will pay more money for contiguous lots, so we often supplement these ponds with groundwater during dry spells to keep levels constant. That's not ideal as groundwater has its own sustainability issues. A smarter approach might be to design ponds that will tolerate greater fluctuations. By excavating deeper for more storage while allowing levels to vary naturally, we could irrigate common areas, boost flood protection, and cut reliance on potable water for landscaping.
We can do far more to treat stormwater as a valuable resource instead of waste. Large flood-control structures like the Addicks and Barker reservoirs already capture huge volumes during major events. Why not hold some of that water after the flood peak passes and use for later irrigation of parks, landscapes, or nearby developments? In areas not yet locked in by development, we should stop building conventional channels (6-ft bottoms, 4:1 slopes, straight gradients) and instead incorporate inline detention and true wet ponds. These increase biodiversity, improve water quality, and keep more water available for irrigation and other beneficial uses.
Houston receives over 40 inches of rain most years which equal about 1.4 million acre-feet across the region, yet only 5–10% infiltrates naturally into our soils each year. It’s time to become hydrophilic again: stop seeing rain as a nuisance to eliminate and start managing it as the precious resource it truly is.
Dr. Culp is the most senior hydrologist at Tetra Land Services and has three decades of civil engineering experience. His Ph.D. scholarship studied the effectiveness of structural BMP for the control of storm water pollution in Harris County while performing water quality monitoring and modeling upon selected ponds for the county. Dr. Culp also co-authored the City of Houston stormwater quality management plan. He is one of Texas’s original Certified Floodplain Managers. Recently, Dr. Culp and his staff have developed a series of drainage studies for Industrial and Oil Majors along the Texas Gulf Coast. Culp is married with two children, and lives on his farm in Southwest Houston.