💧 WQI Calculator™

A full-stack web application to compute the Water Quality Index (WQI) using the standard Weighted Arithmetic Method. Supports manual parameter entry, batch Excel/CSV upload, real-time visualization, and PDF report generation.

🔗 wqi-calculator.onrender.com

• Manual Entry — Add any number of water quality parameters dynamically
• Batch Upload — Upload .xlsx, .xls, or .csv files for bulk calculation
• Exact Precision — Uses Python Decimal library for 7-decimal accurate WQI
• Real-time Charts — Dual-axis bar + line chart (Sub-index & Contribution)
• PDF Report — Download a formatted water quality report with one click
• Load Sample — Pre-loaded with 8 standard WHO/BIS parameters
• Responsive Design — Works on desktop and mobile
• Dark Theme — Professional scientific dashboard aesthetic

The application uses the Brown et al. (1972) Weighted Arithmetic Method:

Note: If Si = 0 (e.g. Total Coliform, Faecal Coliform), qi is treated as 0.
Custom weights can be provided to override the unit-weight formula.

WQI App/
├── app.py                  ← Flask backend + WQI calculation engine
├── requirements.txt        ← Python dependencies
├── render.yaml             ← Render deployment config
├── README.md
├── uploads/                ← Temporary upload storage
├── templates/
│   └── index.html          ← HTML structure
└── static/
    ├── css/
    │   └── style.css       ← Dark theme styling
    └── js/
        └── main.js         ← AJAX, chart, PDF logic

• Python 3.10+
• pip

# 1. Clone the repository
git clone https://github.com/yourusername/wqi-calculator.git
cd wqi-calculator

# 2. Create virtual environment
python3 -m venv venv
source venv/bin/activate        # macOS / Linux
venv\Scripts\activate           # Windows

# 3. Install dependencies
pip install -r requirements.txt

# 4. Run the app
python3 app.py

Open your browser at http://localhost:5000

Your file must contain these columns:

• name — Parameter name
• ci — Observed / measured value
• si — Standard permissible value (0 is allowed)
• weight — Custom weight (leave blank for auto unit-weight 1/Si)

Accepted formats: .xlsx .xls .csv

Calculate WQI from JSON input.

Request:

{
  "parameters": [
    { "name": "pH",  "ci": 7.8, "si": 7.5, "weight": 4 },
    { "name": "DO",  "ci": 7.4, "si": 5.0, "weight": 2 }
  ]
}

Response:

{
  "wqi": 56.7888889,
  "status": "Poor",
  "color": "#f59e0b",
  "parameters": [
    {
      "name": "pH",
      "ci": 7.8,
      "si": 7.5,
      "qi": 104.0,
      "wi_norm": 0.266667,
      "contribution": 27.7333
    }
  ]
}

Upload an Excel or CSV file.

• Body: multipart/form-data with field file
• Returns: Same schema as /calculate + filename

Returns 8 pre-filled sample parameters as JSON.

1. Push code to GitHub
2. Go to render.com → New Web Service
3. Connect your GitHub repository
4. Set:
   • Build Command: pip install -r requirements.txt
   • Start Command: gunicorn app:app
5. Click Deploy

Your app will be live at:

https://your-app-name.onrender.com

This project is licensed under the MIT License — see LICENSE for details.

Aditya Kumar
Built with ❤️ using Flask + Python

© 2025 WQI Calculator™ — All Rights Reserved