Set up temporary drainage swales and sumps – Field Checklist

Definition: Set up temporary drainage swales and sumps for construction teams, verifying sizing, slopes, outfalls, and siltation protection for temporary stormwater control, excluding tie-ins to permanent storm systems.

Verify temporary swale and sump sizing against design peak flows.
Set grades, slopes, and outfalls using laser level and survey.
Install siltation protection, check dams, and stabilized discharge pads.
Interactive, commentable, export with QR code for field traceability.

Start Interactive
Checklist

Set up temporary drainage swales and sumps is the focus of this practical, field-tested checklist. It guides site teams through temporary stormwater swales, construction sumps, and short-term dewatering arrangements, ensuring correct sizing, slope, outfall stabilization, and protection against siltation. The scope deliberately excludes tie-ins or commissioning of permanent storm systems; all steps are for temporary works that protect excavations, haul routes, and stockpiles during construction. By verifying capacities against design flows, setting controlled gradients, and stabilizing outlets with geotextile and rock, you reduce scour, sediment-laden discharges, and unplanned flooding. You’ll capture evidence with photos, turbidity readings, as-built levels, and approvals per approved project specifications and authority requirements. The result is safer, compliant, and maintainable temporary drainage that performs through rain events and phased works. Use this interactive checklist on any device: tick items, leave comments, attach photos and test data, and export to PDF/Excel with a secure QR for traceability.

Ensure temporary drainage functions during construction by verifying swale and sump sizing, achievable slopes, and adequate freeboard against anticipated inflows. Stabilize outfalls to prevent scour and deploy sediment controls to keep turbidity within project limits, backed by documented calculations, photos, and level checks.
Reduce rework and flooding risk by laying out centerlines and invert levels with laser/total station, shaping consistent trapezoidal sections, and installing check dams where grades steepen. Field tolerances and acceptance cues help crews make rapid adjustments before rainfall exposes weaknesses.
Control siltation with geotextiles, sediment bags, coir logs, and silt fences, positioned to intercept fines without impeding flow. Routine inspections after rainfall events and baseline turbidity measurements ensure corrective actions are timely, measurable, and tied to responsible parties.
Interactive online checklist with tick, comment, and export features secured by QR code. Real-time collaboration, embedded photos, calculations, and signatures streamline approvals and handover, ensuring transparent compliance with approved project specifications and authority requirements throughout the temporary works phase.

Planning and Design Verification

1. Confirm the scope covers only temporary swales, sumps, pumps, and outfalls; exclude permanent storm systems. Record scope confirmation with superintendent sign-off and photo of the latest temporary drainage plan.
2. Verify the temporary drainage plan is approved per approved project specifications and authority requirements. Attach approval letter/email and drawing register; acceptance: all drawings latest revision, approvals dated and signed.
3. Check design inflow (L/s) and storage volumes for each swale/sump against catchment areas. Attach calculation sheet; acceptance: capacity ≥ design flow with ≥20% freeboard, reviewer initials and date.

Survey and Layout

4. Stake swale centerlines and sump locations using GNSS/total station. Acceptance: coordinates recorded within ±0.05 m of design; upload CSV of points and overview photos with flags visible.
5. Set invert level benchmarks and grade stakes for swale slopes using a laser level. Acceptance: target slope 0.5–2.0% unless noted; measured slope within ±0.2% of target; record start/end inverts (m).
6. Mark outfall locations, apron extents, and geotextile limits with paint and pins. Acceptance: boundaries match drawings; upload marked-up photo and chainage references.

Swales Excavation and Shaping

7. Excavate swales to design trapezoidal section using excavator and grade control. Acceptance: bottom width and depth within ±50 mm; side slopes uniform; photo with measuring staff and daily checklist signature.
8. Trim and smooth invert to continuous fall using grading bucket. Acceptance: no ponding; straightedge check shows no depressions >10 mm over 10 m; upload level shots at 10 m intervals.
9. Lightly compact side slopes with walk-behind compactor to reduce raveling. Acceptance: firm surface with no sloughing under boot test; photo evidence and compaction pass noted.
10. Install erosion control matting on side slopes steeper than 33% (≈1V:3H). Acceptance: overlaps ≥150 mm, staples ≥2/m², full contact with soil; photos and roll IDs recorded.

Sumps and Pumping

11. Excavate sump pits at low points to design plan dimensions. Acceptance: measured L×W×D within ±50 mm; calculated volume within −5%/+10% of design; freeboard ≥300 mm; upload measurements and photos.
12. Place nonwoven geotextile underlayment in sump and beneath riprap to prevent subgrade scour. Acceptance: overlaps ≥300 mm, no tears; photo and product tag/roll number recorded.
13. Install perimeter sediment barrier (coir log or silt fence) around sump. Acceptance: continuous alignment, fabric keyed-in 150 mm, posts ≤2.0 m spacing; photo and installer initials.
14. Set electric/diesel pumps with screened intake and standby unit. Acceptance: Qpump ≥ design inflow with 100% redundancy; 10-minute test run, record flow (L/s), head (m), voltage/amps; photo of setup.
15. Fit discharge hoses with sediment bag or inline filtration unit before outfall. Acceptance: secure couplings, no leaks, bag intact and accessible; photo pre/post test; record filter model/serial.

Outfalls and Siltation Protection

16. Construct rock riprap apron at discharge over geotextile. Acceptance: thickness and stone size per design; full coverage without gaps; apron length/width within ±100 mm; upload close-up and wide-angle photos.
17. Install check dams in swales where grades require flow attenuation. Acceptance: crest at least 150 mm below banks; spacing ensures toe-to-toe contact; photo and chainage of each dam recorded.
18. Install level spreader or diffuser at outfall to convert to sheet flow. Acceptance: uniform dispersion with no visible rills after test discharge; photo and short video attached.
19. Install silt fence/coir logs as final control downstream of apron. Acceptance: posts embedded ≥500 mm, fabric buried 150 mm, tight to ground; photo and fence length measured.
20. Provide stabilized crossing where haul routes intersect swales using 150 mm crushed rock over geotextile. Acceptance: no rutting >50 mm; no sediment tracking beyond 10 m; photo and truck pass count logged.

Monitoring and Handover

21. Record baseline turbidity upstream and at discharge using a calibrated meter. Acceptance: meter calibration log attached; during pump-out, discharge turbidity within project limits; values (NTU) logged with timestamp.
22. Complete as-built survey of swale inverts, sump bottoms, and outfall elevations. Acceptance: levels within ±10 mm of design; redline drawing exported and signed by surveyor.
23. Set inspection schedule: daily visual checks and after rainfall >10 mm/24 h. Acceptance: inspection log with photos, defects/actions recorded, responsible person and due dates assigned.
24. Compile handover pack: approvals, calculations, surveys, pump tests, turbidity logs, and photos. Acceptance: digital signatures from superintendent and environmental lead; export PDF/Excel with QR code.

Right-sizing Swales and Sumps with Achievable Slopes

Temporary drainage must match real inflows and site grades. Start by confirming catchment areas and expected inflow rates, then test whether proposed swale slopes (typically 0.5–2.0%) are buildable with available cut/fill. A shallow, continuous fall is better than a steep, erodible channel; if grades are flat, increase width or add sumps to maintain capacity and reduce velocities. Provide at least 20% freeboard to accommodate rainfall uncertainty and debris. Shape consistent trapezoids to simplify maintenance and measurement. Survey each 10 m to verify invert falls stay within ±0.2% of target and to detect low spots that collect silt. Sumps at low points should have measured volume within −5%/+10% of design and at least 300 mm freeboard. Document assumptions and field adjustments with annotated photos and redlines to keep reviewers aligned with what was actually built.

Target swale slopes between 0.5–2.0% unless drawings state otherwise.
Maintain ≥20% freeboard in swales and sumps for resilience.
Survey inverts every 10 m; accept ±0.2% slope variance.
Verify sump volume within −5%/+10% of design.
Attach calculations, survey CSVs, and redlines.

Stable Outfalls and Energy Dissipation

Outfalls are where temporary systems usually fail. Protect the discharge by laying nonwoven geotextile and placing riprap to the specified thickness and stone size, ensuring full coverage and intimate contact with the subgrade. Where concentrated flow exits hoses or pipes, add a diffuser or level spreader to convert jets into sheet flow. On graded swales, check dams help reduce velocities and trap coarse sediment; their crests must sit below banks and spacing should allow toe-to-toe contact. After a controlled test release or pump run, inspect for rilling, displacement, or undermining. Capture wide-angle and close-up photos and note any remedial stone placement. Use stabilized crossings where traffic intersects swales so vehicles don’t rut channels and mobilize fines, and keep the discharge path free from sharp bends that kink hoses and concentrate energy.

Geotextile under riprap; ensure full coverage and overlap.
Riprap thickness and size per design; verify by spot checks.
Use level spreaders to disperse concentrated flows.
Check dams crest below banks; toe-to-toe spacing.
Test discharge and photograph before/after conditions.

Controlling Siltation and Proving Performance

Sediment controls must intercept fines without choking flow. Install silt fences with proper burial, coir logs keyed to the ground, and sediment bags on pump discharges. Place geotextile beneath rock to stop subgrade pumping. Establish baseline turbidity upstream and monitor discharge during pump-out, recording NTU and calibration status. Keep daily inspections and rain-event checks, clearing debris and repairing undermined aprons or tilted fences. If turbidity trends upward, add a second sediment bag, extend the apron, or reduce pump rate. Evidence matters: geotag photos of controls, record lengths and quantities, document corrective actions, and secure digital signatures. All acceptance remains per approved project specifications and authority requirements, ensuring the temporary drainage is robust, auditable, and ready for rapid adaptation as the site evolves through phases.

Measure turbidity; record NTU and meter calibration.
Bury silt fence 150 mm; posts ≤2.0 m spacing.
Use sediment bags on discharge hoses.
Geotag photos of every installed control.
Log inspections after ≥10 mm rainfall.

How to Use This Interactive Swales & Sumps Checklist

Preparation: gather laser level, total station/GNSS, tape and staff, turbidity meter, pumps and hoses, geotextile, riprap, sediment bags, PPE, and the approved temporary drainage plan with design flows and levels.
Site readiness: confirm safe access, locate underground services, define exclusion zones around excavations, and brief crews on temporary works limits and emergency pump-down procedures.
Start interactive mode: open the checklist on your device, create a project, assign roles (superintendent, surveyor, environmental lead), and enable comments and photo uploads.
Execute and record: tick items as built, attach calculations, level logs, photos, and turbidity readings; note variances and approvals per approved project specifications and authority requirements.
Export and share: generate PDF/Excel with embedded photos and a QR code for authentication; distribute to stakeholders and store in the project document control system.
Sign-off: capture digital signatures from the superintendent and environmental lead; archive the signed export and schedule follow-up inspections and rain-event checks.

Call to Action

Isla McGregor SafetyIsla

Nov 09, 2025

FAQ

Question: What slope should I aim for in temporary swales to avoid erosion and ponding?

Aim for a consistent fall between 0.5% and 2.0% unless drawings specify otherwise. This range keeps velocities manageable while preventing ponding. Verify with a laser level at 10 m intervals. If grades are too flat, widen the swale or add sumps and check dams to maintain capacity.

Question: How do I size pumps for temporary sumps on a construction site?

Size pumps to meet or exceed the design inflow with redundancy. Provide a standby unit and run a 10‑minute test, recording flow rate (L/s), head (m), and electrical readings. Use screened intakes and sediment bags on discharge hoses. Document results and approvals per approved project specifications and authority requirements.

Question: What outfall protection should I use for temporary hose discharges?

Install nonwoven geotextile and riprap sized to the design, ensuring full coverage without gaps. Where flow is concentrated, add a diffuser or level spreader to achieve sheet flow. After a controlled discharge, inspect for rills, undermining, or displacement, and document with photos before accepting the outfall as stable.

Question: How can I prevent siltation from clogging swales and sumps?

Combine controls: silt fences with proper burial, coir logs keyed to ground, geotextile under rock, and sediment bags on discharges. Keep routine inspections, especially after >10 mm rainfall. If turbidity increases, add controls or reduce pump rate. Record NTU readings, photos, and corrective actions for traceability.

Question: When should temporary drainage be modified or extended during the project?

Modify when catchment areas change, rainfall exceeds assumptions, or inspections show erosion or overtopping risk. Update layout as the site phases shift, adding check dams, extending aprons, or resizing sumps. Document revisions with redlines, photos, and approvals to keep the system effective and compliant.