Reservoir Discharge Hydrograph Tuning for Riparian Denitrification

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Solution Overview

Problem

Existing reservoir operation methods focus on social and economic functions, neglecting ecological needs and water quality improvement, particularly in dammed rivers, leading to nitrogen pollution and eutrophication.

Innovation Solution

A method for optimizing reservoir discharge hydrograph based on nitrogen water quality improvement, involving a riparian zone nitrogen transport and transformation numerical model to determine the A/T ratio threshold for flood waves, maximizing denitrification capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If reservoir operation focuses on social and economic functions, then economic benefits are maximized, but ecological needs and water quality improvement are neglected

Engineering Contradiction:

Improveeconomic benefitsVSAvoidnitrogen pollution

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operational parameters of the reservoir by optimizing the discharge hydrograph based on nitrogen removal capacity. It introduces a nitrogen removal capacity index and uses flood wave characteristics (amplitude A and duration T) as key parameters to control reservoir discharge, transforming the operation from purely economic to ecologically-informed parameter control

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent establishes a feedback mechanism by using a riparian zone nitrogen transport and transformation numerical model to simulate and evaluate nitrogen removal capacity. The simulation results feed back into the discharge hydrograph optimization, creating a closed-loop system where water quality outcomes inform operational decisions

Inventive Principle:

Principle #23Feedback

2Reliability

If reservoir operation uses traditional flood control and economic operation methods, then social and economic tasks are fulfilled, but nitrogen accumulates in water bodies

Engineering Contradiction:

Improveflood control capabilityVSAvoidnitrogen accumulation

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent transforms static reservoir operation rules into dynamic discharge hydrographs that adapt to different flood wave conditions. By considering the amplitude and duration of flood waves, the operation scheme dynamically adjusts discharge timing and magnitude to maximize nitrogen removal while maintaining flood control

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs periodic flood wave discharge patterns to enhance nitrogen removal. By creating controlled periodic fluctuations in water level and flow, it promotes water exchange between the river channel and riparian zone, facilitating periodic nitrogen uptake by vegetation and sediments

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If multi-objective ecological operation is implemented, then ecological compensation is achieved, but water quality improvement research remains scarce

Engineering Contradiction:

Improveecological compensationVSAvoidoperation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent focuses on a specific local mechanism - the riparian zone's nitrogen removal function - rather than attempting to address all ecological objectives simultaneously. By concentrating on the nitrogen transport and transformation processes in the riparian zone, it simplifies the complex multi-objective problem into a targeted water quality improvement approach

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances nitrogen removal efficiency by 10% in dammed rivers, improving water quality and ecological conditions downstream.

Implementation Method 1

establishing a riparian zone nitrogen transport and transformation numerical model to simulate a denitrification level of the riparian zone under different flood wave conditions

Methodology Applied

Scientific EffectDenitrification: Anaerobic Digestion

Data Source

PatentUS12579348B2Method, device, medium and electronic device for improving nitrogen water quality of dammed river based on reservoir operation

Publication Date: 2026.03.17 NANJING HYDRAULIC RES INST

AI summary

The present belongs to the technical field of reservoir operation, including following steps: selecting a dammed river to be tested, determining a study area in a riparian zone downstream of a dam, obtaining historical long-sequence water level data of the study area, and analyzing duration and amplitude variation ranges of a historical water level; setting a plurality of groups of flood waves according to the duration and amplitude variation ranges; establishing a riparian zone nitrogen transport and transformation numerical model to simulate a denitrification level of the riparian zone under different flood wave conditions; obtaining an A/T ratio value of one flood wave corresponding to a maximum value of denitrification capacity of the riparian zone according to results of all cases; and taking the obtained A/T ratio value as a threshold of a reservoir discharge hydrograph.