The Core Finding (The Sideways Ditch)
The Problem: A Structural Design Conflict at the Base Shelf
To manage mountain stormwater runoff, the City of Phoenix shifted the project framework toward a massive horizontal expansion behind our neighborhood curve. The channel footprint was widened sideways, which required clearing a significant swath of pristine native desert vegetation and placing an expansive concrete track directly adjacent to private rear property boundaries.
From an open-channel hydraulics standpoint, spreading rapid mountain runoff across this horizontally expanded floor maximizes surface boundary friction. This configuration forces incoming high-velocity stormwater to slow down abruptly upon transition. Because the water’s carrying capacity drops along with its velocity, suspended mountain gravel and sediment are expected to drop out of suspension rapidly. This wide design essentially creates a structural silt trap that risks choking the channel’s active volume during high-intensity storm events, introducing a foreseeable overtopping hazard to previously secure residential properties while permanently replacing a natural preserve view corridor with an expansive infrastructure footprint.
While our community fully respects the municipality’s objective to modernize regional drainage, engineering safety requires absolute verification over assumption. We operate on a foundation of professional transparency: we respect the city’s intent, but we rely strictly on verified empirical data to protect our homes. Because the current design completely alters the historical containment track of the watershed by expanding horizontally, the neighborhood alliance requires documented, multi-year hydraulic modeling to prove that this wide layout does not introduce an unmanaged lateral risk vector to our property foundations.
| ### 📑 Public Impact | ###🏠 Technical Brief | ###📲 Citizen Science |
| The real estate reality. Disclosure traps. | The cold laws of physics. Read the barometric telemetry and fluid velocity calculations. | Replicate our work. See the step-by-step guide to tracking paths using standard apps. |
Requested Technical Information
As local residents, our priority is ensuring long-term watershed safety and safeguarding the structural stability of our neighborhood’s boundary walls. To build a transparent partnership with city engineering teams, we have submitted a formal technical review request for the following critical records:
- 1. Project Drainage Study & Hydrology Report
- Why we need it: To verify the baseline 100-year peak design storm runoff calculations ($Q_{\text{peak}} = 115\text{ CFS}$) entering the channel footprint from the preserve foothills.
- 2. Channel Cross-Section Profiles
- Why we need it: To audit the maximum design flow depths and calculated freeboard safety margins directly running adjacent to our private property fences.
- 3. Open-Channel Hydraulic Calculations
- Why we need it: To review how the city’s math accounts for the sudden 50.7% velocity reduction ($19.86\text{ ft/s}$ down to $9.78\text{ ft/s}$) that chokes the channel shelf.
- 4. Sediment Management & Maintenance Protocol
- Why we need it: To ensure the city has a long-term erosion-control protocol to protect our foundations since the 5-meter strip of native desert root anchors was cleared.