Stormwater and Drainage Construction in Aurora and the Southeast Metro
Detention ponds, storm sewer, inlets and erosion control for commercial, school and multifamily sites in Aurora, Centennial, Parker and Castle Rock.
Cherry Creek Dam is 141 feet high and 14,300 feet long at its crest, and it exists because water in this part of the metro does not arrive politely. Summer storms can drop a season's worth of rain in an hour onto parking lots, rooftops and bare graded soil, and the site designed to receive it has to hold, slow and release that flow in a way the city will accept. We build the detention, conveyance and treatment systems that make that possible.
Stormwater is the part of a commercial project that municipal reviewers ask about first and revisit most often. They want to know where the water goes, how fast it leaves, and what is in it when it does. We manage construction of the storm sewer, inlets, culverts, outfalls and detention basins that answer those questions, and we document each stage with the survey and inspection records that closeout requires.
We work for developers laying out new pads, school districts adding campuses and owners retrofitting older properties whose drainage no longer meets current criteria.
Drainage criteria, reports and the review path
Every parcel in this metro answers to a drainage report and grading plan reviewed by the city or county where it sits. The reviewer checks the design storm assumptions, the release rates from detention, the capacity of the downstream system and the water quality measures. Aurora, Centennial, Parker and Castle Rock each have their own staff and criteria, so a detail approved in one city cannot be assumed to pass in the next. We read the approved drainage report as the governing document and build to it, rather than to a simplified set of details.
Construction stormwater is a separate track. Sites that disturb enough ground need a stormwater management plan, installed controls and regular inspections, and those obligations belong to whoever is running the work that day. We keep the plan current on site, log inspections, and correct deficiencies quickly. The trade partner team for grading ties these controls to the earthwork described under mass grading, so the sediment basin is built before the first cut rather than after the first storm.
Building detention and conveyance in the right order
The sequence matters as much as the details. Outfalls and downstream connections go in first so that every pipe upstream drains to something real. Detention basins are excavated early, since they double as temporary sediment traps during construction, then finished to the permanent outlet structure and landscaping once the site is stable. Inlets and storm sewer follow the paving subgrade so that grades can be verified with the paving contractor before pipes are covered.
We check pipe inverts, slopes and structure elevations by survey at each stage, not just at the end. A storm sewer that is an inch or two off can be tolerable on paper and still hold water in a drive aisle, and corrections after paving cost far more than corrections in the trench. When a project includes broader site development and utilities, we coordinate crossings with water and sanitary lines in advance so that gravity systems keep their slope.
What our stormwater scope covers
Typical work includes reinforced concrete and HDPE storm pipe, manholes, curb and area inlets, concrete outlet structures, riprap aprons, trickle channels and forebays, plus the rock and vegetation that stabilize the finished basin. For retrofits we cut into existing systems, install underground detention or filtration units, and repair failed outfalls, all while keeping the site open to tenants.
Water quality features are increasingly part of the package. Aurora Reservoir provides drinking water to the City of Aurora, and only electric boats are permitted to protect water quality, so runoff quality is not an abstract concern in this part of the metro. We install permanent features such as sand filters, rain gardens and water quality outlets to the details the engineer approved and document the soil and plant materials so that maintenance responsibility can be handed over cleanly. Parking fields from parking lot construction are the largest source of runoff on most commercial sites, so those two scopes are planned together.
Trench safety and confined spaces
Storm sewer work involves deep trenches, heavy pipe and equipment working close to open excavations. We design every trench with the appropriate sloping, shoring or trench boxes, keep spoil back from the edge, and run a competent person inspection at the start of each shift and after rain. Utility locates are confirmed before digging, and potholing is used wherever records are uncertain.
Basins and large pipes bring confined space and drowning risks. We fence open basins, install ladders and egress points, and treat large manholes and culverts as permit-required spaces when the conditions call for it. Weather monitoring is part of the daily plan, since a thunderstorm upstream can send water into a trench much faster than the crew can climb out.
How drainage work connects to the rest of the project
Drainage touches almost every other service we offer. It shapes the pad elevations we set during grading, the slab edges for truck courts and dock aprons, and the commissioning documents we assemble at the end. Owners who need public-facing infrastructure, such as the roads, trails and parks within a master-planned community, often bring us in through the government and public sector channel.
Large public and open space assets give the region its drainage character. Cherry Creek State Park covers 3,346 acres around an 880-acre reservoir, and its nearby neighbors in the Cherry Creek State Park area live with the consequences of flood control every day. We use that context when we explain to a developer why a city engineer is asking for a particular release rate.
Bring us the drainage report
Share the approved drainage report and grading plan and we will lay out the order of work, the inspections the city will expect and a realistic price. If the project is part of a larger development, our team can also review how it fits the Aurora Highlands community systems.
Questions Owners Ask
When does a site need detention?
Almost always for new commercial development, because adding roofs and pavement increases both the volume and the peak rate of runoff. The city's drainage criteria and the downstream system determine whether detention is on site, shared with neighboring parcels or paid for through a fee in lieu. Your civil engineer's drainage report will state the answer, and we price whichever option the city approves.
Who is responsible for maintaining a detention pond after construction?
Usually the property owner or an owners' association, under a maintenance agreement recorded with the project. We turn over the as-built survey, outlet details and a maintenance outline so that the owner knows what to inspect. Cities in this metro often inspect basins, so keeping the outlet structure clear matters.
Can storm sewer work happen in winter?
Yes, with planning. Frozen ground, cold concrete and slow compaction raise costs, but trenching and pipe installation can continue with blankets, heated enclosures for structures and careful backfill. We avoid placing fill on frozen ground and schedule precast structures to arrive when the crew is ready to set them.
How do you handle a basin that holds water after it is finished?
We first check the as-built survey against the design to see whether the grades are wrong or the soil is slow to drain. Fixes range from regrading and clearing the outlet to installing an underdrain when the engineer approves it. We document the corrective work so that the city inspector can close out the item.
Do you design drainage systems?
No, the civil engineer of record designs them, and we build to the approved drawings. We do help during preconstruction by reviewing constructability, offering pipe and structure alternatives that meet the criteria, and pricing options before the plans are final.